[Mailman-Users] keep back mails of users

[Martin Held]

hi

i'm a beginner and i have a question. perhaps somebody of 
you know the answer.

i created a new list for mailman.
now a want 2 kinds of users:
- the first group should be able to send the mail directly to mailman and
mailman
should dispose the mail to the list members.
- the second group of users can send mails too. but the mail needs a release
by
the administrator. 

is this possible ?

how ?

thanks for help

best regards
emmi