Well, in the time since we've opened this discussion I called back my provider (for the 3rd time) and found a support person that took the time to really work through the problem with me. The solution was to set up some rules using the Rules Wizard and specifying the subject line "Returned mail see transcript for details" Not a complete solution, as some of the messages have a slightly different header but certainly a workaround that will serve to eliminate about 98% of them.
Thanks anyway.
JB