I'm not sure if it would fit your need, but I extracted the following
from the XMAILER logs.  Since you already have to run a mailer,
probably the XMAILER, to run Listserv, this might fit in easily
with you need, or could be easily tailored by starting with the
DEFRT exit from XMAILER.  I believe the comments below were
in reference to a very similar question.
Harry
 
Received: by MARIST (Mailer X1.25) id 4420; Wed, 27 Jul 88 15:00:01 EDT
Date:         Wed, 27 Jul 88 11:40:18 CDT
Reply-To:     The Crosswell Mailer List <XMAILER@MARIST>
Sender:       The Crosswell Mailer List <XMAILER@MARIST>
From:         John Voigt - Academic Systems Programmer
              <[log in to unmask]>
Subject:      Re: Hardcopy exit?
To:           "A. Harry Williams" <HARRY@MARIST>
In-Reply-To:  Message of Wed, 27 Jul 88 11:07:32 EDT from <JEFF@UTCVM>
 
Actually, you don't really need an EXIT to make something work.  You
might want one for verification or managing internal mail (campus mail)
addressing or somesuch but I found the following works just fine:
 
in the "outgoing" section:
 
HARDCOPY.Tulane.EDU LPRT HARDCOPY DEFRT 1 TRUNCATE
 
LPRT is the name of an RSCS printer.  The truncate option allows mail
to be addressed like:
 
"Prof. Fred Jones" <[log in to unmask]>
 
We have had this for quite some time although no one is really using it.
 
John/