[Exim] Need quick help.

Hey,

I need some quick help. I know this has been done before, but I'm
confused. I need pop3 accounts for several domains, and I need the pop3
accounts to not have system accounts, and I need one postmaster type
system account for each domain to be able to set up aliases and
accounts. Finally, I need the users in different domains to be unique,
that is:
tom@???
tom@localhost
tom@???

Please point me toward some docs to get me started. I have managed to
get exim doing what my stock sendmail did, RH 6.1 Now I need the extra
stuff.

Thanks,
Paul