Chris,
At risk of using a sledgehammer to kill a fly... have you thought about
doing the following?
1) Do a scan for worldnet addresses. Copy this list somewhere (into a text
file, etc.)
2) Quiet delete all worldnet addresses.
3) Quiet bulk add all the worldnet addresses but the problem one.
Sure, it ain't elegant, but I think it'd work, no? :)
Regards,
Adam the temporarily sigless