[Exim] Exim 3.12

Hi there,

I have read through all the archives. Took ages to download :)

Anyway, I didn't happen to find a fix to the problem I have.

I have a client using a Debian 2.2 server running exim 3.12 as their MTA for
a Citrix Server.
All clients attach through Outlook 97. They compose their mails in outlook
and all mail works excellently.
The client has a small I.T. department and want to charge each department
for "Internet access"
They have decided to make Internal email a prerequsite for all staff members
and want to charge each users
department R 100 per "Internet connection"

How do I make exim limit the users from being able to send email to remote
networks? at this stage, all clients
are able to send email to any address. I need to somehow make exim allow
only a selected few (possibly a group file ?)
the ability to send mail outside the local domain.

Any suggestions would be most appreciated.
Please mail me directly as I have not subscribed to this mailing list.

Many thanks
Gary

{Dont fight the river, let it flow}