[exim] Filter Rule - Detecting if message originated on my s…

This should be easy. How do I create a conditional to detect email
generated on my server from something like Mailman - or movable type -
or other software running on my server?

--
Marc Perkel - marc@???

Spam Filter: http://www.junkemailfilter.com
    My Blog: http://marc.perkel.com
My Religion: http://www.churchofreality.org
~ "If it's real - we believe in it!" ~