How to get bounced messages sent to sender and not just list owner.

[Steve Rifkin <steve410 @ cs . jhu . edu>]

Now, that I've got restrict2post working, when someone outside the restrict 
lists sends to the list, the list owner gets a bounced (non-member submission) 
message.

How do I get some kind of customized bounced message sent back to the sender as 
well?

There are some lists here that for the senders that are non-members and produce 
a bounce, we want to send a message back to them automatically with some 
site-details.

Thanks!

Steve