Receiving bounces from different servers at one account
 

I'm sending emails from 6 different servers... all use the Sendmail masquerade feature and are claiming to be mail.mydomain.com (bogus domain, obviously). Emails are coming from different users @mydomain.com. All emails come from a script that runs in root's cron.

Right now, if I log onto all the individual servers and open up pine as root, I see bounces... some say 'unknown' user. Others say "failed" for whatever reason... connection timeout, etc.

I want to setup each box to send all failures and bounces back to the originating address... not into the local root mbox. ie: if loser@mydomain.com sends an email to an invalid address, I want it to bounce to that user. If tt@mydomain.com sends one and the connection is refused, I want tt to get the bounce. I don't want these to bounce to root on the local machine. Is this done through /etc/aliases? Through Sendmail's virtusertable? A combination of both?

The closet I've gotten so far is to point mailer-daemon and postmaster at root, then send root to myself@mydomain.com via /etc/aliases. However this means that myself@mydomain.com also gets normal cron emails, etc.

How do I make this work?