is there a way to find orphaned relations somehow? i'm envisioning a use case something like the IAM case, where you've got users and roles and entities and role_bindings, and you go to remove a user from a role_binding but that's all you do, so you've still got relations between the role_binding and the role and the role_binding and the entity. is there a way to find those relations which are orphaned such that you could do a periodic garbage-collection on those orphaned role bindings, or does it really come down to cleaning up all transitive relations when you remove the user from the role_binding?