considering you have no control over who joins a Unity making sure you have the right people is literally impossible. I have a better idea, customizable filters, like "no posts displayed with less than 10 characters" or something. idiot A can still do "1", "2" and you never have to know he even logged in.
or do like I do, turn off the chat channel unless you are actively searching for someone to do a wanted or something, just like I have shout and yell turned off most of the time.