fix multiple policy issue

ml-agents/mlagents/trainers/ghost/trainer.py

         """
         # Get policy based on team id, but not group id
         parsed_behavior_id = BehaviorIdentifiers.from_name_behavior_id(name_behavior_id)
+        # So that the parsed behavior id is there for new groups
+        if parsed_behavior_id.behavior_id not in self._name_to_parsed_behavior_id:
+            self._name_to_parsed_behavior_id[
+                parsed_behavior_id.behavior_id
+            ] = parsed_behavior_id
         name_behavior_id = create_name_behavior_id(
             parsed_behavior_id.brain_name, team_id=parsed_behavior_id.team_id
         )

ml-agents/mlagents/trainers/trainer_controller.py

         self.train_model = train
         self.param_manager = param_manager
         self.ghost_controller = self.trainer_factory.ghost_controller
+        self.team_ids: List[int] = []
         self.registered_behavior_ids: Set[str] = set()
 
         self.trainer_threads: List[threading.Thread] = []
                 )
                 self.trainer_threads.append(trainerthread)
 
-        policy = trainer.create_policy(
-            parsed_behavior_id, env_manager.training_behaviors[name_behavior_id]
-        )
-        trainer.add_policy(parsed_behavior_id, policy)
+        if parsed_behavior_id.team_id not in self.team_ids:
+            policy = trainer.create_policy(
+                parsed_behavior_id, env_manager.training_behaviors[name_behavior_id]
+            )
+            trainer.add_policy(parsed_behavior_id, policy)
+            self.team_ids.append(parsed_behavior_id.team_id)
+        else:
+            policy = trainer.get_policy(name_behavior_id)
 
         agent_manager = AgentManager(
             policy,