*community - oops
I think that groups should by default the same way as xenforo forums itselves do, so it should not display them if there is no inherited permission given. It will be flexible in the same way, because you can always give permission to allow user to view the page. It should of course not only look for forum specific permissions, but also for global ones. Social groups is cool, but hard to learn, because it somehow breaks with the basic user flow and way xenforo is setup (in my opinion). It works, but it is pretty hard to understand that.