Yes... you've there are a few options...
Depending on your programming skill, you could write your own SMTP gateway (C++, VB, etc). This gateway would receive your bounced emails and handle them accordingly. Probably not in the realm for most people.
Another option would be to have a mailbox that these emails come back to (which you already have setup obviously). Then you can utilize one of several commerical COM objects out there to sift through that mailbox using POP3 (ServerObjects - AspPOP3). Now that you can go through the messages, search for key phrases, and do what you need to. Now, here's the kicker. You'll have to wrap this around some type of schedulable routine. If you know VB or C++, you could write a app to use this COM object and schedule it. Another option is to put it in an ActiveX object of a DTS Package in MS SQL Server and schedule it through the DB server. If both of those aren't an option, you could write it into an ASP page, but you'll have to go to the page manually to execute it.
That which does not kill me postpones the inevitable.