Not at the moment, but this wouldn't be too difficult. Records are shared under the /keybase/private/user1,user2,user3/kbsecret hierarchy, so adding or removing a user would just be a matter of changing the user list (moving the directory) and updating the session to match.
> And I assume every single member of the team has to independently set up the session?
Nope! This is a huge benefit of KBFS - the session is shared with all members immediately.
Edit: Oh, I see what you mean by "set up the session." The session files are shared with all members immediately, but each member needs to tell their own copy of `kbsecret` to load that session.
Now that KBSecret uses its own hierarchy, there are ways to fix that. I just hadn't thought of it before ;)