Hi @Feynman10 ,
Tribe currently supports this through Groups.
If I attempt to understand your question more, I think you're asking whether you want to be able to create a Group, and then allow your members to create subgroups within that Group.
If that is the case, in Tribe v2 (our upcoming version of Tribe) we are introducing "Spaces" (the current equivalent of Groups) which will allow you to create sub-spaces within a space. Unfortunately, this is currently not available on Tribe.
Hope that clarifies things for you.