I have a couple of PHB's who insist on misspelling a couple of domain names. Then that email sits in the queue for several days before it times out and bounces back. Of course, if the intended recipient does not get the email immediately, they have to resend the email with the incorrect domain name 10 or 20 times.

I need a way to set up a list of these 10 domains they insist on sending email to so that when they send the email, the email is immediately bounced back to them

Any suggestions?