[Mailman-Users] configurations

Hi there, please help with my configuration problem.

I want to create a list where only a few select can post to it. This is no problem with Mailman but if a non-priviledged user posts to the list it goes into the "posting held for approval" section where I (the list admin) discard all postings. Is there a way to discard all non priviledged users?

Thanks in inticipation, Dat