Changing MemberList Items

Is there a way to change the items displayed in the memberlist (ie. add/remove) while it is displayed?

I noticed that I receive an error when I try to add/remove while it is open, but I would really like to modify the list contents to be more specific as the user types. I can do that now but I get a flicker from having to close and open the list at each keystroke.

Anyway to do this???

Thanks