procmail as outgoing mail filter?

From:                   Mark Tiramani <markjt(_at_)fredo(_dot_)co(_dot_)uk>
To:                     procmail(_at_)informatik(_dot_)rwth-aachen(_dot_)de
Subject:                outgoing mail filtering?
(re-send)

I have the horrible feeling I've missed something obvious, so appologies
if I have, but after searching what I believe to be the right sources I
have not yet found any reference to the following:

I need to implement a system-wide outgoing mail filter that essentially
uses the same core procmail filter set I have for incoming mail. It's for
two 300+ user organisations that need to protect the outside world from
internal garbage/viruses adn also add disclaimers etc. to all messages
bound for the Internet.

Sorry again if I'm just being dense on this one, but any ideas or pointers
are appreciated.

Mark

Mark Tiramani
FREDO Internet Services
markjt(_at_)fredo(_dot_)co(_dot_)uk