This would be indeed really nice to have. That way you could also have private groups that can for example discuss more sensitive questions or stuff related to the administration of the site etc.
There is something like groups in the Q2A database, i.e. every user gets a number assigned that reflects their administrative status. "120" for example is Super Administrator.
I tried extracting it for using it as groups in Dokuwiki, but I failed finding a good way to convert the TINYINT into a VARCHAR, see some documentation on the issue here: