The exchange server gets mail from a catchall address with the ISP by using a POP3 connector. It then routes email to exchange users based on the address in the TO: or the CC:.
All is working well except mail sent to the catchall that doesn't have a user's email address in the TO or CC, like a mail blast. Mail blasts are typically coming to us with their own address in the TO: field, with all the recipients in the BCC field.
Is there a way to route to people based on something else in the email? Obviously we can't route by BCC, but hoping there is another potential identifier that I don't know about.