diff --git a/src/backend/distributed/planner/fast_path_router_planner.c b/src/backend/distributed/planner/fast_path_router_planner.c
index 0d4840652..80afc7afa 100644
--- a/src/backend/distributed/planner/fast_path_router_planner.c
+++ b/src/backend/distributed/planner/fast_path_router_planner.c
@@ -273,8 +273,16 @@ FastPathRouterQuery(Query *query, FastPathRestrictionContext *fastPathContext)
 		return true;
 	}
 
-	/* make sure that the only range table in FROM clause */
-	if (list_length(query->rtable) != 1)
+	int numFromRels = list_length(query->rtable);
+
+	/* make sure that there is only one range table in FROM clause */
+	if ((numFromRels != 1)
+#if PG_VERSION_NUM >= PG_VERSION_18
+
+	    /* with a PG18+ twist for GROUP rte - if present make sure there's two range tables */
+		&& (!query->hasGroupRTE || numFromRels != 2)
+#endif
+		)
 	{
 		return false;
 	}
diff --git a/src/backend/distributed/planner/multi_router_planner.c b/src/backend/distributed/planner/multi_router_planner.c
index 017dceef6..14ce199c8 100644
--- a/src/backend/distributed/planner/multi_router_planner.c
+++ b/src/backend/distributed/planner/multi_router_planner.c
@@ -2192,7 +2192,11 @@ CheckAndBuildDelayedFastPathPlan(DistributedPlanningContext *planContext,
 static bool
 ConvertToQueryOnShard(Query *query, Oid citusTableOid, Oid shardId)
 {
-	Assert(list_length(query->rtable) == 1);
+	Assert(list_length(query->rtable) == 1
+	#if PG_VERSION_NUM >= PG_VERSION_18
+		   || (list_length(query->rtable) == 2 && query->hasGroupRTE)
+	#endif
+		   );
 	RangeTblEntry *citusTableRte = (RangeTblEntry *) linitial(query->rtable);
 	Assert(citusTableRte->relid == citusTableOid);