In-queue rejections

[Daniel L. Miller]

I don't know what the correct terminology is for my question - please 
adjust my wording as needed.

When a user mistypes a remote e-mail address (not that THAT ever 
happens!), the result is typically either a "user unknown", "invalid 
recipient", or "host or domain not found" message.  At least for MY 
system, with MY configuration (however flawed it may be), this results 
in a couple messages floating in the send queue with these statuses.  
Periodically, I'll check for such items, notify my users of a problem, 
and delete them from the queue.

I do have a bounce_template_file, and I've TRIED to make it a bit more 
informative - but my users still cross their eyes and call me and 
complain that OUR mail server is broken!

Is there a more advanced option that can give individual messages 
instead of a generic bounce message?  Something that might parse the 
rejection and give specific advice to the computer illiterate?

Also, is there any e-mail interface for canceling messages?  So that if 
a slightly more competent user actually READS the bounce message, 
determines that they spelled it wrong - they can tell the mail server to 
cancel the send?
--
Daniel