diff --git a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
index fc5e0e48dc3..6d2ce73624f 100644
--- a/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
+++ b/litellm/proxy/pass_through_endpoints/pass_through_endpoints.py
@@ -233,15 +233,7 @@ async def chat_completion_pass_through_endpoint(
         # skip router if user passed their key
         if "api_key" in data:
             llm_response = asyncio.create_task(litellm.aadapter_completion(**data))
-        elif llm_router is not None and data["model"] in router_model_names:  # model in router model list
-            llm_response = asyncio.create_task(llm_router.aadapter_completion(**data))
-        elif (
-            llm_router is not None
-            and llm_router.model_group_alias is not None
-            and data["model"] in llm_router.model_group_alias
-        ):  # model set in model_group_alias
-            llm_response = asyncio.create_task(llm_router.aadapter_completion(**data))
-        elif llm_router is not None and llm_router.has_model_id(data["model"]):  # model in router model list
+        elif llm_router is not None and llm_router.is_recognized_model(data["model"]):
             llm_response = asyncio.create_task(llm_router.aadapter_completion(**data))
         elif (
             llm_router is not None
diff --git a/litellm/proxy/response_api_endpoints/endpoints.py b/litellm/proxy/response_api_endpoints/endpoints.py
index e5ba5182bed..807ac073cb3 100644
--- a/litellm/proxy/response_api_endpoints/endpoints.py
+++ b/litellm/proxy/response_api_endpoints/endpoints.py
@@ -121,7 +121,7 @@ def _parse_cursor_model_variant(model: str) -> _CursorModelVariant:
 def _router_can_serve(model: str, llm_router: "Router | None") -> bool:
     if llm_router is None:
         return False
-    if model in llm_router.model_names or model in llm_router.model_group_alias:
+    if llm_router.is_recognized_model(model):
         return True
     if model in llm_router.team_public_model_names:
         return True
diff --git a/litellm/proxy/route_llm_request.py b/litellm/proxy/route_llm_request.py
index dd8deed57f1..b347360a939 100644
--- a/litellm/proxy/route_llm_request.py
+++ b/litellm/proxy/route_llm_request.py
@@ -587,16 +587,10 @@ async def route_request(
             return getattr(llm_router, f"{route_type}")(**data)
 
         elif (
-            (
-                is_proxy_admin_without_team
-                and data["model"] not in router_model_names
-                and data["model"] in llm_router.team_public_model_names
-            )
-            or data["model"] in router_model_names
-            or llm_router.has_model_id(data["model"])
-            or llm_router.model_group_alias is not None
-            and data["model"] in llm_router.model_group_alias
-        ):
+            is_proxy_admin_without_team
+            and data["model"] not in router_model_names
+            and data["model"] in llm_router.team_public_model_names
+        ) or llm_router.is_recognized_model(data["model"]):
             return getattr(llm_router, f"{route_type}")(**data)
 
         elif data["model"] not in router_model_names:
diff --git a/litellm/router.py b/litellm/router.py
index aa2a98d5c23..8917ef60e36 100644
--- a/litellm/router.py
+++ b/litellm/router.py
@@ -54,6 +54,7 @@ from litellm.litellm_core_utils.asyncify import run_async_function
 from litellm.litellm_core_utils.core_helpers import (
     _get_parent_otel_span_from_kwargs,
     coerce_token_limit,
+    get_litellm_metadata_from_kwargs,
     get_metadata_variable_name_from_kwargs,
     get_or_create_metadata_bucket,
 )
@@ -608,8 +609,10 @@ class Router:
         self.team_public_model_names: frozenset[str] = frozenset()
 
         # Initialize cache attributes that ``_invalidate_model_group_info_cache``
-        # touches *before* the first ``set_model_list`` below (which calls
-        # that invalidation as part of building the model index).
+        # and ``_invalidate_access_groups_cache`` touch *before* the first
+        # ``set_model_list`` below (which calls those invalidations as part of
+        # building the model index) and before ``_init_routing_groups(None)``
+        # (which calls them on every group rebuild).
         self._access_groups_cache: dict[str, list[str]] | None = None
         # Per-router cache for the proxy auth-layer "is this model explicitly
         # zero-cost?" check. Lives on the router so it is invalidated alongside
@@ -617,6 +620,8 @@ class Router:
         # ``id()``-reuse risk after GC). See
         # ``litellm.proxy.auth.auth_checks._is_model_cost_zero``.
         self._zero_cost_cache: dict[str, bool] = {}
+        self._routing_group_rows: tuple[DeploymentTypedDict, ...] | None = None
+        self._init_routing_groups(None)
 
         self.deployment_affinity_ttl_seconds = deployment_affinity_ttl_seconds
         self.model_group_affinity_config = model_group_affinity_config
@@ -1039,6 +1044,8 @@ class Router:
         self._routing_groups: dict[str, RoutingGroup] = {}
         self._model_to_group: dict[str, str] = {}
         self._group_selectors: dict[str, dict[str, RouterStrategySelector]] = {}
+        self._invalidate_model_group_info_cache()
+        self._invalidate_access_groups_cache()
 
         if not groups_input:
             return
@@ -1053,6 +1060,12 @@ class Router:
                 raise ValueError("routing_groups: group_name must be non-empty.")
             if group.group_name == "default":
                 raise ValueError("routing_groups: 'default' is reserved for the implicit fallback group.")
+            if group.group_name in known_model_names or group.group_name in (self.model_group_alias or {}):
+                verbose_router_logger.warning(
+                    "routing_groups: group_name '%s' is shadowed by an existing model_name or model_group_alias; "
+                    "the group's strategy still applies to its members, but the name is not callable until renamed.",
+                    group.group_name,
+                )
             if group.group_name in seen_group_names:
                 raise ValueError(
                     f"routing_groups: group names must be unique, duplicate group_name '{group.group_name}'."
@@ -1089,6 +1102,82 @@ class Router:
                 {strategy_value: group_selector} if group_selector is not None else {}
             )
 
+    def get_routing_group(self, model_name: str) -> RoutingGroup | None:
+        """
+        The routing group callable as `model_name`, or None. A real deployment
+        `model_name` added after init shadows a same-named group (mirroring
+        `_try_early_resolve_deployments_for_model_not_in_names`, where concrete
+        models win over indirection); config-time collisions are rejected by
+        `_init_routing_groups`.
+        """
+        if not self._routing_groups:
+            return None
+        group: Final = self._routing_groups.get(model_name)
+        if (
+            group is None
+            or model_name in self.model_name_to_deployment_indices
+            or model_name in (self.model_group_alias or {})
+        ):
+            return None
+        return group
+
+    def _get_routing_group_deployments(
+        self, model: str, team_id: str | None = None
+    ) -> list[DeploymentTypedDict] | None:  # mutable-ok: list matches _get_all_deployments' contract for callers
+        """
+        The union of member deployments for a routing group called as `model`,
+        or None when `model` is not a callable group. The requested name stays
+        the group name so strategy selectors key their state by it.
+
+        `_common_checks_available_deployment` consults this BEFORE its
+        early-resolve step so a wildcard `default_deployment` or pattern route
+        cannot hijack a group call. Overall resolution precedence there:
+        specific deployment > model id > model_group_alias > routing group >
+        model_name > team/pattern/default fallbacks.
+        """
+        if not self._routing_groups:
+            return None
+        routing_group: Final = self.get_routing_group(model)
+        if routing_group is None:
+            return None
+        return [  # mutable-ok: matches _get_all_deployments' list contract expected by downstream filters
+            deployment
+            for member in routing_group.models
+            for deployment in self._get_all_deployments(model_name=member, team_id=team_id)
+        ]
+
+    def is_recognized_model(self, model: str) -> bool:
+        """
+        Whether `model` names something this router serves directly: a
+        deployment model_name, a deployment id, a `model_group_alias`, or a
+        callable routing group. Proxy request gates share this predicate so a
+        new virtual-model kind cannot be forgotten at one of them; wildcard,
+        default-deployment, and deployment-name fallbacks stay caller policy.
+        """
+        return (
+            model in self.model_names
+            or self.has_model_id(model)
+            or (self.model_group_alias is not None and model in self.model_group_alias)
+            or self.get_routing_group(model) is not None
+        )
+
+    def routing_group_has_alternatives(self, model_group: str | None) -> bool:
+        """
+        True when `model_group` names a callable routing group whose member
+        union spans more than one deployment. Cooldown handling passes the
+        FAILING REQUEST's model group here: a 429 on a group call cools the
+        member down so selection moves to the group's alternatives, while a
+        direct call to a single-deployment member keeps the
+        single-deployment-model-group cooldown exemption.
+        """
+        if model_group is None:
+            return False
+        resolved: Final = self._get_model_from_alias(model=model_group) or model_group
+        group: Final = self.get_routing_group(resolved)
+        if group is None:
+            return False
+        return sum(len(self.model_name_to_deployment_indices.get(member) or ()) for member in group.models) > 1
+
     _OVERRIDABLE_ROUTING_STRATEGIES: frozenset[str] = frozenset({"simple-shuffle", *_DEFAULT_SELECTOR_ATTR_BY_STRATEGY})
 
     def _get_request_routing_strategy_override(self, request_kwargs: dict | None) -> str | None:
@@ -1149,8 +1238,10 @@ class Router:
         the most specific expression of caller intent.
 
         Otherwise every model belongs to exactly one group: an explicit entry
-        from `routing_groups`, or the implicit `"default"` group driven by the
-        router's top-level `routing_strategy` / `routing_strategy_args`.
+        from `routing_groups` (either because `model` IS a callable group name,
+        or because it is a member of one), or the implicit `"default"` group
+        driven by the router's top-level `routing_strategy` /
+        `routing_strategy_args`.
 
         `self.routing_strategy` may be either a string or a `RoutingStrategy`
         enum member (the constructor accepts both), so it is normalized to a
@@ -1162,7 +1253,7 @@ class Router:
             verbose_router_logger.debug("routing_group=request-override model=%s strategy=%s", model, override)
             return override, self._get_override_strategy_selector(override)
 
-        group_name: Final = self._model_to_group.get(model)
+        group_name: Final = model if self.get_routing_group(model) is not None else self._model_to_group.get(model)
         if group_name is None:
             strategy = self._normalize_strategy(self.routing_strategy)
             attr: Final = self._DEFAULT_SELECTOR_ATTR_BY_STRATEGY.get(strategy or "")
@@ -7143,6 +7234,7 @@ class Router:
                     original_exception=exception,
                     deployment=deployment_id,
                     time_to_cooldown=_time_to_cooldown,
+                    requested_model_group=(get_litellm_metadata_from_kwargs(kwargs) or {}).get("model_group"),
                 )  # setting deployment_id in cooldown deployments
 
                 return result
@@ -8326,6 +8418,7 @@ class Router:
                 self.model_name_to_deployment_indices[model_name] = updated_indices
             else:
                 del self.model_name_to_deployment_indices[model_name]
+                self.model_names.discard(model_name)
 
         # Update team_model_to_deployment_indices
         for key, indices in list(self.team_model_to_deployment_indices.items()):
@@ -9981,6 +10074,52 @@ class Router:
 
         return returned_models
 
+    def get_model_list_from_routing_groups(self, model_name: str | None = None) -> Sequence[DeploymentTypedDict]:
+        """
+        Callable routing groups materialized as model-list rows, mirroring
+        `get_model_list_from_model_alias`: each member deployment is emitted
+        under the group's name (via `_get_all_deployments`' `model_alias`
+        rewrite), which is what surfaces groups in `get_model_names`,
+        `/v1/models` discovery, `get_model_group_usage`, and the
+        blocked/unhealthy hiding that all read `get_model_list`.
+        """
+        if model_name is not None:
+            group: Final = self.get_routing_group(model_name)
+            return self._materialize_routing_group_rows((group,)) if group is not None else ()
+        cached: Final = self._routing_group_rows
+        if cached is not None:
+            return cached
+        rows: Final = self._materialize_routing_group_rows(
+            tuple(
+                callable_group
+                for name in self._routing_groups
+                if (callable_group := self.get_routing_group(name)) is not None
+            )
+        )
+        self._routing_group_rows = rows
+        return rows
+
+    def _materialize_routing_group_rows(self, groups: tuple[RoutingGroup, ...]) -> tuple[DeploymentTypedDict, ...]:
+        return tuple(
+            self._as_routing_group_row(deployment)
+            for group in groups
+            for member in group.models
+            for deployment in self._get_all_deployments(model_name=member, model_alias=group.group_name)
+        )
+
+    @staticmethod
+    def _as_routing_group_row(deployment: DeploymentTypedDict) -> DeploymentTypedDict:
+        """
+        A member deployment re-emitted under its group's name must not carry
+        the member's `access_groups`: access groups grant member names, never
+        the group, so inheriting them here would let a key holding a member's
+        access group list and call the whole group.
+        """
+        model_info: Final = {  # mutable-ok: DeploymentTypedDict rows are plain dicts
+            k: v for k, v in (deployment.get("model_info") or {}).items() if k != "access_groups"
+        }
+        return {**deployment, "model_info": model_info}  # mutable-ok: DeploymentTypedDict rows are plain dicts
+
     def get_model_list(
         self, model_name: str | None = None, team_id: str | None = None
     ) -> list[DeploymentTypedDict] | None:
@@ -9997,6 +10136,7 @@ class Router:
             returned_models.extend(self._get_all_deployments(model_name=model_name, team_id=team_id))
 
         returned_models.extend(self.get_model_list_from_model_alias(model_name=model_name))
+        returned_models.extend(self.get_model_list_from_routing_groups(model_name=model_name))
 
         if len(returned_models) == 0:  # check if wildcard route
             potential_wildcard_models: Final = self.pattern_router.route(model_name) or []
@@ -10028,6 +10168,7 @@ class Router:
         """
         self._cached_get_model_group_info.cache_clear()
         self._zero_cost_cache.clear()
+        self._routing_group_rows = None
 
     def _invalidate_access_groups_cache(self) -> None:
         """Invalidate the cached access groups.
@@ -10598,17 +10739,23 @@ class Router:
         if _model_from_alias is not None:
             model = _model_from_alias
 
-        early: Final = self._try_early_resolve_deployments_for_model_not_in_names(
-            model=model,
-            request_team_id=request_team_id,
-            include_team_models=_is_proxy_admin_request(request_kwargs),
-        )
-        if early is not None:
-            return early
+        _routing_group_deployments: Final = self._get_routing_group_deployments(model=model, team_id=request_team_id)
+        if _routing_group_deployments is None:
+            early: Final = self._try_early_resolve_deployments_for_model_not_in_names(
+                model=model,
+                request_team_id=request_team_id,
+                include_team_models=_is_proxy_admin_request(request_kwargs),
+            )
+            if early is not None:
+                return early
 
         ## get healthy deployments
         ### get all deployments
-        healthy_deployments = self._get_all_deployments(model_name=model, team_id=request_team_id)
+        healthy_deployments = (
+            _routing_group_deployments
+            if _routing_group_deployments is not None
+            else self._get_all_deployments(model_name=model, team_id=request_team_id)
+        )
         _pre_model_access_group_filter_len: Final = len(healthy_deployments)
         healthy_deployments = self._filter_deployments_by_model_access_groups(
             model=model,
diff --git a/litellm/router_utils/cooldown_handlers.py b/litellm/router_utils/cooldown_handlers.py
index 39618a6f182..86d9bb5c3ed 100644
--- a/litellm/router_utils/cooldown_handlers.py
+++ b/litellm/router_utils/cooldown_handlers.py
@@ -319,6 +319,7 @@ def _should_cooldown_deployment(
     deployment: str,
     exception_status: str | int,
     original_exception: Any,
+    requested_model_group: str | None = None,
 ) -> bool:
     """
     Helper that decides if a deployment should be put in cooldown
@@ -341,7 +342,9 @@ def _should_cooldown_deployment(
     model_group: Final = litellm_router_instance.get_model_group(id=deployment)
     is_single_deployment_model_group = False
     if model_group is not None and len(model_group) == 1:
-        is_single_deployment_model_group = True
+        is_single_deployment_model_group = not litellm_router_instance.routing_group_has_alternatives(
+            requested_model_group
+        )
 
     ## CHECK DEPLOYMENT-LEVEL POLICY FIRST (overrides router-level)
     dep_policy, dep_allowed_fails = _get_deployment_cooldown_policy(litellm_router_instance, deployment)
@@ -413,6 +416,7 @@ def _set_cooldown_deployments(
     exception_status: str | int,
     deployment: str | None = None,
     time_to_cooldown: float | None = None,
+    requested_model_group: str | None = None,
 ) -> bool:
     """
     Add a model to the list of models being cooled down for that minute, if it exceeds the allowed fails / minute
@@ -449,6 +453,7 @@ def _set_cooldown_deployments(
         deployment=deployment,
         exception_status=exception_status,
         original_exception=original_exception,
+        requested_model_group=requested_model_group,
     ):
         litellm_router_instance.cooldown_cache.add_deployment_to_cooldown(
             model_id=deployment,
diff --git a/tests/test_litellm/proxy/response_api_endpoints/test_endpoints.py b/tests/test_litellm/proxy/response_api_endpoints/test_endpoints.py
index a064c8de985..079454d963f 100644
--- a/tests/test_litellm/proxy/response_api_endpoints/test_endpoints.py
+++ b/tests/test_litellm/proxy/response_api_endpoints/test_endpoints.py
@@ -1480,6 +1480,12 @@ def _router_serving_only(base_model: str) -> MagicMock:
     mock_router.model_names = set()
     mock_router.model_group_alias = {}
     mock_router.team_public_model_names = frozenset()
+    mock_router.is_recognized_model.side_effect = lambda model: (
+        model in mock_router.model_names or model in mock_router.model_group_alias
+    )
+    mock_router.router_general_settings.pass_through_all_models = False
+    mock_router.default_deployment = None
+    mock_router.pattern_router.patterns = {base_model: ["anthropic/*"]}
     mock_router.pattern_router.get_pattern.side_effect = (
         lambda model: [{"model_name": "anthropic/*"}] if model == base_model else None
     )
@@ -1723,3 +1729,22 @@ class TestCursorVariantResolvedBeforeAuth:
         )
         assert auth_body["model"] == "claude-opus-5-thinking-high"
         assert "reasoning_effort" not in auth_body
+
+
+class TestCursorGateRecognizesRoutingGroups:
+    def test_group_name_variant_is_not_mangled(self):
+        from litellm import Router
+        from litellm.proxy.response_api_endpoints.endpoints import _resolve_cursor_model_variant
+
+        router = Router(
+            model_list=[
+                {"model_name": "member-fast", "litellm_params": {"model": "openai/gpt-4o", "api_key": "fake"}}
+            ],
+            routing_groups=[
+                {"group_name": "grouped-thinking-high", "models": ["member-fast"], "routing_strategy": "simple-shuffle"}
+            ],
+        )
+        body = {"model": "grouped-thinking-high", "messages": [{"role": "user", "content": "hi"}]}
+        resolved = _resolve_cursor_model_variant(body, router)
+        assert resolved["model"] == "grouped-thinking-high"
+        assert "reasoning_effort" not in resolved
diff --git a/tests/test_litellm/proxy/test_route_a2a_models.py b/tests/test_litellm/proxy/test_route_a2a_models.py
index 616fa62cda5..02e4bddcee0 100644
--- a/tests/test_litellm/proxy/test_route_a2a_models.py
+++ b/tests/test_litellm/proxy/test_route_a2a_models.py
@@ -32,6 +32,7 @@ async def test_route_a2a_model_bypasses_router():
     mock_router.model_names = ["gpt-4", "gpt-3.5-turbo"]
     mock_router.deployment_names = []
     mock_router.has_model_id = Mock(return_value=False)
+    mock_router.is_recognized_model = Mock(return_value=False)
     mock_router.model_group_alias = None
     mock_router.router_general_settings = Mock(pass_through_all_models=False)
     mock_router.default_deployment = None
@@ -88,6 +89,7 @@ async def test_route_non_a2a_model_raises_error_if_not_in_router():
     mock_router.model_names = ["gpt-4", "gpt-3.5-turbo"]
     mock_router.deployment_names = []
     mock_router.has_model_id = Mock(return_value=False)
+    mock_router.is_recognized_model = Mock(return_value=False)
     mock_router.model_group_alias = None
     mock_router.router_general_settings = Mock(pass_through_all_models=False)
     mock_router.default_deployment = None
diff --git a/tests/test_litellm/proxy/test_route_llm_request.py b/tests/test_litellm/proxy/test_route_llm_request.py
index 3ae0e1e7d18..08e26125bd3 100644
--- a/tests/test_litellm/proxy/test_route_llm_request.py
+++ b/tests/test_litellm/proxy/test_route_llm_request.py
@@ -1091,3 +1091,27 @@ async def test_route_request_rejects_chat_completion_without_messages():
     assert exc_info.value.status_code == 400
     assert exc_info.value.param == "messages"
     llm_router.acompletion.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_route_request_routing_group_name_passes_model_gate():
+    from unittest.mock import AsyncMock, patch
+
+    from litellm import Router
+
+    router = Router(
+        model_list=[
+            {"model_name": "member-a", "litellm_params": {"model": "openai/gpt-4o", "api_key": "sk-test"}},
+            {"model_name": "member-b", "litellm_params": {"model": "openai/gpt-4o-mini", "api_key": "sk-test"}},
+        ],
+        routing_groups=[
+            {"group_name": "grouped-quality", "models": ["member-a", "member-b"], "routing_strategy": "simple-shuffle"}
+        ],
+    )
+    data = {"model": "grouped-quality", "messages": [{"role": "user", "content": "hi"}]}
+
+    with patch.object(router, "acompletion", new=AsyncMock(return_value="group_response")) as spy:
+        response = await (await route_request(data, router, None, "acompletion"))
+
+    assert response == "group_response"
+    spy.assert_called_once_with(**data)
diff --git a/tests/test_litellm/router_strategy/test_router_routing_groups.py b/tests/test_litellm/router_strategy/test_router_routing_groups.py
index b8dcdacd8a3..7d1ed796996 100644
--- a/tests/test_litellm/router_strategy/test_router_routing_groups.py
+++ b/tests/test_litellm/router_strategy/test_router_routing_groups.py
@@ -726,3 +726,345 @@ def test_strategy_reinit_unregisters_override_selectors():
     assert router._override_selectors == {}
     assert not any(id(cb) == id(override_selector) for cb in litellm.callbacks)
     assert router._get_override_strategy_selector("latency-based-routing") is router.lowestlatency_logger
+
+
+def _quality_group(strategy="latency-based-routing"):
+    return [{"group_name": "quality", "models": ["filtered-model", "other-model"], "routing_strategy": strategy}]
+
+
+def test_group_name_is_callable_and_unions_member_deployments():
+    router = _build_router(routing_groups=_quality_group())
+    model, deployments = router._common_checks_available_deployment(model="quality")
+    assert model == "quality"
+    assert sorted(d["model_info"]["id"] for d in deployments) == ["deploy-1", "deploy-2", "deploy-3"]
+
+
+def test_group_name_appears_in_model_names_and_model_list():
+    router = _build_router(routing_groups=_quality_group())
+    assert "quality" in router.get_model_names()
+    rows = router.get_model_list(model_name="quality")
+    assert {r["model_name"] for r in rows} == {"quality"}
+    assert sorted(r["model_info"]["id"] for r in rows) == ["deploy-1", "deploy-2", "deploy-3"]
+
+
+def test_get_routing_context_for_group_name_uses_group_strategy():
+    router = _build_router(routing_groups=_quality_group())
+    strategy, selector = router._get_routing_context("quality")
+    assert strategy == "latency-based-routing"
+    assert selector is router._group_selectors["quality"]["latency-based-routing"]
+
+
+@pytest.mark.asyncio
+async def test_group_call_dispatches_via_group_selector():
+    router = _build_router(routing_groups=_quality_group())
+    group_selector = router._group_selectors["quality"]["latency-based-routing"]
+
+    with (
+        patch.object(
+            group_selector,
+            "async_get_available_deployments",
+            wraps=group_selector.async_get_available_deployments,
+        ) as latency_spy,
+        patch("litellm.router.simple_shuffle", wraps=litellm.router.simple_shuffle) as shuffle_spy,
+    ):
+        deployment = await router.async_get_available_deployment(model="quality", request_kwargs={})
+
+        assert latency_spy.called
+        assert not shuffle_spy.called
+        assert deployment["model_name"] in {"filtered-model", "other-model"}
+
+
+def test_group_name_colliding_with_model_name_is_shadowed_with_warning(caplog):
+    import logging
+
+    with caplog.at_level(logging.WARNING, logger="LiteLLM Router"):
+        router = _build_router(
+            routing_groups=[
+                {"group_name": "filtered-model", "models": ["other-model"], "routing_strategy": "latency-based-routing"}
+            ]
+        )
+    assert any("shadowed" in record.getMessage() for record in caplog.records)
+    assert router.get_routing_group("filtered-model") is None
+    assert router._get_routing_context("other-model")[0] == "latency-based-routing"
+
+    model, deployments = router._common_checks_available_deployment(model="filtered-model")
+    assert sorted(d["model_info"]["id"] for d in deployments) == ["deploy-1", "deploy-2"]
+
+
+def test_group_name_colliding_with_model_group_alias_is_shadowed_with_warning(caplog):
+    import logging
+
+    with caplog.at_level(logging.WARNING, logger="LiteLLM Router"):
+        router = Router(
+            model_list=_model_list(),
+            model_group_alias={"quality": "filtered-model"},
+            routing_groups=_quality_group(),
+        )
+    assert any("shadowed" in record.getMessage() for record in caplog.records)
+    assert router.get_routing_group("quality") is None
+
+    model, deployments = router._common_checks_available_deployment(model="quality")
+    assert model == "filtered-model"
+    assert sorted(d["model_info"]["id"] for d in deployments) == ["deploy-1", "deploy-2"]
+
+
+def test_real_model_added_later_shadows_group():
+    router = _build_router(routing_groups=_quality_group())
+    assert router.get_routing_group("quality") is not None
+
+    from litellm.types.router import Deployment
+
+    router.add_deployment(
+        Deployment(
+            model_name="quality",
+            litellm_params={"model": "openai/gpt-4o", "api_key": "sk-test-4", "api_base": "https://example.invalid"},
+            model_info={"id": "deploy-shadow"},
+        )
+    )
+    assert router.get_routing_group("quality") is None
+    model, deployments = router._common_checks_available_deployment(model="quality")
+    assert [d["model_info"]["id"] for d in deployments] == ["deploy-shadow"]
+
+    router.delete_deployment(id="deploy-shadow")
+    assert "quality" not in router.model_names
+    assert router.get_routing_group("quality") is not None
+    _, restored = router._common_checks_available_deployment(model="quality")
+    assert sorted(d["model_info"]["id"] for d in restored) == ["deploy-1", "deploy-2", "deploy-3"]
+
+
+def test_group_with_no_member_deployments_raises_no_healthy():
+    router = Router(
+        model_list=_model_list(),
+        routing_groups=[{"group_name": "empty-group", "models": ["ghost-model"], "routing_strategy": "simple-shuffle"}],
+    )
+    with pytest.raises(litellm.BadRequestError):
+        router._common_checks_available_deployment(model="empty-group")
+
+
+def test_alias_pointing_at_group_composes():
+    router = Router(
+        model_list=_model_list(),
+        model_group_alias={"quality-alias": "quality"},
+        routing_groups=_quality_group(),
+    )
+    model, deployments = router._common_checks_available_deployment(model="quality-alias")
+    assert model == "quality"
+    assert sorted(d["model_info"]["id"] for d in deployments) == ["deploy-1", "deploy-2", "deploy-3"]
+
+
+def test_model_group_info_reports_group():
+    router = _build_router(routing_groups=_quality_group())
+    info = router.get_model_group_info("quality")
+    assert info is not None
+    assert info.model_group == "quality"
+    assert "openai" in info.providers
+
+
+def test_routing_group_has_alternatives():
+    router = _build_router(routing_groups=_quality_group())
+    assert router.routing_group_has_alternatives("quality") is True
+    assert router.routing_group_has_alternatives("filtered-model") is False
+    assert router.routing_group_has_alternatives(None) is False
+
+    solo_router = Router(
+        model_list=_model_list(),
+        routing_groups=[{"group_name": "solo-group", "models": ["other-model"], "routing_strategy": "simple-shuffle"}],
+    )
+    assert solo_router.routing_group_has_alternatives("solo-group") is False
+
+
+def test_member_direct_call_unchanged_by_callable_groups():
+    router = _build_router(routing_groups=_quality_group())
+    model, deployments = router._common_checks_available_deployment(model="other-model")
+    assert model == "other-model"
+    assert [d["model_info"]["id"] for d in deployments] == ["deploy-3"]
+
+
+def test_update_settings_group_change_invalidates_model_group_info():
+    router = _build_router(routing_groups=_quality_group())
+    assert router.get_model_group_info("quality") is not None
+    assert router.get_model_group_info("renamed-group") is None
+
+    router.update_settings(
+        routing_groups=[
+            {"group_name": "renamed-group", "models": ["filtered-model"], "routing_strategy": "simple-shuffle"}
+        ]
+    )
+    assert router.get_model_group_info("quality") is None
+    info = router.get_model_group_info("renamed-group")
+    assert info is not None
+    assert info.model_group == "renamed-group"
+
+
+def test_is_recognized_model_covers_every_virtual_model_kind():
+    router = Router(
+        model_list=_model_list(),
+        model_group_alias={"my-alias": "filtered-model"},
+        routing_groups=_quality_group(),
+    )
+    assert router.is_recognized_model("filtered-model") is True
+    assert router.is_recognized_model("deploy-1") is True
+    assert router.is_recognized_model("my-alias") is True
+    assert router.is_recognized_model("quality") is True
+    assert router.is_recognized_model("ghost") is False
+
+
+def test_routing_group_has_alternatives_resolves_aliases():
+    router = Router(
+        model_list=_model_list(),
+        model_group_alias={"quality-alias": "quality"},
+        routing_groups=_quality_group(),
+    )
+    assert router.routing_group_has_alternatives("quality-alias") is True
+    assert router.routing_group_has_alternatives("quality") is True
+
+
+def test_group_rows_cache_invalidated_on_model_list_change():
+    from litellm.types.router import Deployment
+
+    router = _build_router(routing_groups=_quality_group())
+    assert sum(1 for row in router.get_model_list() if row["model_name"] == "quality") == 3
+
+    router.add_deployment(
+        Deployment(
+            model_name="filtered-model",
+            litellm_params={"model": "openai/gpt-4o", "api_key": "sk-test-5", "api_base": "https://example.invalid"},
+            model_info={"id": "deploy-4"},
+        )
+    )
+    assert sum(1 for row in router.get_model_list() if row["model_name"] == "quality") == 4
+
+
+def _pin_choice_to(deployment_id):
+    def _pick(seq):
+        for candidate in seq:
+            if candidate["model_info"]["id"] == deployment_id:
+                return candidate
+        return seq[0]
+
+    return _pick
+
+
+async def _call_and_get_cooldowns(router, model):
+    from litellm.router_utils.cooldown_handlers import _async_get_cooldown_deployments
+
+    with (
+        patch("litellm.router_strategy.simple_shuffle.random.choice", side_effect=_pin_choice_to("deploy-3")),
+        pytest.raises(litellm.RateLimitError),
+    ):
+        await router.acompletion(
+            model=model,
+            messages=[{"role": "user", "content": "hi"}],
+            mock_response="litellm.RateLimitError",
+        )
+    return await _async_get_cooldown_deployments(litellm_router_instance=router, parent_otel_span=None)
+
+
+@pytest.mark.asyncio
+async def test_group_call_429_registers_cooldown_end_to_end():
+    router = Router(
+        model_list=_model_list(),
+        routing_groups=_quality_group("simple-shuffle"),
+        num_retries=0,
+        cooldown_time=60,
+    )
+    cooldown_ids = await _call_and_get_cooldowns(router, "quality")
+    assert "deploy-3" in cooldown_ids
+
+
+@pytest.mark.asyncio
+async def test_alias_to_group_429_registers_cooldown_end_to_end():
+    router = Router(
+        model_list=_model_list(),
+        model_group_alias={"quality-alias": "quality"},
+        routing_groups=_quality_group("simple-shuffle"),
+        num_retries=0,
+        cooldown_time=60,
+    )
+    cooldown_ids = await _call_and_get_cooldowns(router, "quality-alias")
+    assert "deploy-3" in cooldown_ids
+
+
+@pytest.mark.asyncio
+async def test_direct_single_deployment_member_429_keeps_exemption_end_to_end():
+    router = Router(
+        model_list=_model_list(),
+        routing_groups=_quality_group("simple-shuffle"),
+        num_retries=0,
+        cooldown_time=60,
+    )
+    cooldown_ids = await _call_and_get_cooldowns(router, "other-model")
+    assert "deploy-3" not in cooldown_ids
+
+
+def test_group_rows_do_not_inherit_member_access_groups():
+    router = Router(
+        model_list=[
+            {
+                "model_name": "gated-member",
+                "litellm_params": {"model": "openai/gpt-4o", "api_key": "sk-test"},
+                "model_info": {"id": "gated-1", "access_groups": ["restricted-team"]},
+            }
+        ],
+        routing_groups=[
+            {"group_name": "gated-group", "models": ["gated-member"], "routing_strategy": "simple-shuffle"}
+        ],
+    )
+    access_groups = router.get_model_access_groups()
+    assert "gated-group" not in access_groups.get("restricted-team", [])
+    assert all("access_groups" not in (row.get("model_info") or {}) for row in router.get_model_list(model_name="gated-group"))
+    assert "access_groups" in router.get_model_list(model_name="gated-member")[0]["model_info"]
+
+
+def test_group_rebuild_invalidates_access_groups_cache():
+    router = _build_router(routing_groups=_quality_group())
+    router.get_model_access_groups()
+    assert router._access_groups_cache is not None
+
+    router.update_settings(routing_groups=[])
+    assert router._access_groups_cache is None
+
+
+def test_get_model_list_from_routing_groups_materializes_rows():
+    router = _build_router(routing_groups=_quality_group())
+    rows = router.get_model_list_from_routing_groups()
+    assert {row["model_name"] for row in rows} == {"quality"}
+    assert router.get_model_list_from_routing_groups() is rows
+
+    named = router.get_model_list_from_routing_groups(model_name="quality")
+    assert sorted(row["model_info"]["id"] for row in named) == ["deploy-1", "deploy-2", "deploy-3"]
+    assert router.get_model_list_from_routing_groups(model_name="filtered-model") == ()
+
+
+def test_get_routing_group_deployments_unions_members():
+    router = _build_router(routing_groups=_quality_group())
+    union = router._get_routing_group_deployments("quality")
+    assert sorted(d["model_info"]["id"] for d in union) == ["deploy-1", "deploy-2", "deploy-3"]
+    assert router._get_routing_group_deployments("filtered-model") is None
+
+
+def test_materialize_routing_group_rows_labels_members_with_group_name():
+    router = _build_router(routing_groups=_quality_group())
+    group = router.get_routing_group("quality")
+    rows = router._materialize_routing_group_rows((group,))
+    assert {row["model_name"] for row in rows} == {"quality"}
+    assert len(rows) == 3
+
+
+def test_as_routing_group_row_strips_access_groups():
+    source = {"model_name": "member", "model_info": {"id": "d1", "access_groups": ["restricted"]}}
+    row = Router._as_routing_group_row(source)
+    assert row["model_info"] == {"id": "d1"}
+    assert source["model_info"]["access_groups"] == ["restricted"]
+
+
+@pytest.mark.asyncio
+async def test_group_call_429_cools_down_member_across_retries():
+    router = Router(
+        model_list=_model_list(),
+        routing_groups=_quality_group("simple-shuffle"),
+        num_retries=1,
+        cooldown_time=60,
+    )
+    cooldown_ids = await _call_and_get_cooldowns(router, "quality")
+    assert "deploy-3" in cooldown_ids
diff --git a/tests/test_litellm/router_utils/test_cooldown_handlers.py b/tests/test_litellm/router_utils/test_cooldown_handlers.py
index 2139521d2a8..4768988fc87 100644
--- a/tests/test_litellm/router_utils/test_cooldown_handlers.py
+++ b/tests/test_litellm/router_utils/test_cooldown_handlers.py
@@ -296,3 +296,84 @@ class TestShouldCooldownBasedOnAllowedFailsPolicy:
         assert set_cache_call[1]["ttl"] == 0.0, (
             "cooldown_time_override=0 should be used as TTL, not the router-level 60.0"
         )
+
+
+class TestRoutingGroupCooldownAlternatives:
+    def _router(self, routing_groups=None):
+        from litellm import Router
+
+        return Router(
+            model_list=[
+                {
+                    "model_name": "solo-member",
+                    "litellm_params": {"model": "openai/gpt-4o", "api_key": "sk-test"},
+                    "model_info": {"id": "cg-deploy-1"},
+                },
+                {
+                    "model_name": "other-member",
+                    "litellm_params": {"model": "openai/gpt-4o-mini", "api_key": "sk-test"},
+                    "model_info": {"id": "cg-deploy-2"},
+                },
+            ],
+            routing_groups=routing_groups,
+        )
+
+    def test_group_call_429_cools_down_member_with_alternatives(self):
+        from litellm.router_utils.cooldown_handlers import _should_cooldown_deployment
+
+        router = self._router(
+            routing_groups=[
+                {
+                    "group_name": "grouped",
+                    "models": ["solo-member", "other-member"],
+                    "routing_strategy": "simple-shuffle",
+                }
+            ]
+        )
+        assert (
+            _should_cooldown_deployment(
+                litellm_router_instance=router,
+                deployment="cg-deploy-1",
+                exception_status=429,
+                original_exception=Exception("rate limited"),
+                requested_model_group="grouped",
+            )
+            is True
+        )
+
+    def test_direct_member_429_keeps_single_deployment_exemption(self):
+        from litellm.router_utils.cooldown_handlers import _should_cooldown_deployment
+
+        router = self._router(
+            routing_groups=[
+                {
+                    "group_name": "grouped",
+                    "models": ["solo-member", "other-member"],
+                    "routing_strategy": "simple-shuffle",
+                }
+            ]
+        )
+        assert (
+            _should_cooldown_deployment(
+                litellm_router_instance=router,
+                deployment="cg-deploy-1",
+                exception_status=429,
+                original_exception=Exception("rate limited"),
+                requested_model_group="solo-member",
+            )
+            is False
+        )
+
+    def test_429_without_request_context_keeps_exemption(self):
+        from litellm.router_utils.cooldown_handlers import _should_cooldown_deployment
+
+        router = self._router(routing_groups=None)
+        assert (
+            _should_cooldown_deployment(
+                litellm_router_instance=router,
+                deployment="cg-deploy-1",
+                exception_status=429,
+                original_exception=Exception("rate limited"),
+            )
+            is False
+        )