[Mailman-Users] restrictions needed

[ian stanley]

Running:
GNU Mailman over postfix

Problem:

I need to setup a departmental mailing list[s], say       

      test at lists.<our_domain_name> 

I must allow posting to other users at our domain [who may/not be on the list]

Posting should be available from dialup  users who are working from home - 
who will have a mail from address of 

     username@<our domain name>

I must also allow posting to other users who are on the list but not on the 
domain [eg external suppliers etc]


Is this to be done in postfix or Mailman?

t.i.a.


Ian Stanley