I read your recent tip on handling ex-employee e-mail. I think it wouldn be easier to create a catch all group
- Create a group called Old Employees.
- DO NOT add anyone to the group.
- E-mail-enable this group.
- Assign this group to accept e-mails for all old accounts.
It may take awhile to list all the ex-employees' e-mails, but it's worth it. The Group will accept all their e-mails, but since there's no one in the group, it just drops the e-mail. No NDR, mo bad mail, no maintenance, and you can add up to 200 e-mails per group (I think).