Have a blueprint to inherit owning teams from multiple blueprints and agregate the teams. I.e. In a model with Application > Project > Portfolio blueprints, Application should be able to inherit ownership from both Project and Portfolio, while Project should be able to inherit from Portfolio while also having its own owning teams (i.e. project may have a 'Managers' team that can manage that project and Applications on it but not the entire Porftolio).