We have a gaming clan that has members worldwide. We want to have the
ability to email freely between all members registered with the server
from anywhere in the world but only from their clan email address.
Another idea. Put all of the valid addresses in a distribution list and then use a scan list filter to only accept mail from the email addresses on the list. The filter would look like the following rule. In this case is the address is not in the dist. list friends'pml is gets moved to a spam user mail directory. I use this with another rule to block mail to a mailing list.