We are using an Exchange Server 2010. I have created a transport rule that inspects the subject field from users outside the organization for words like Invoice, Receipt, Statement, etc. I have the email redirected to an account for spam. In the exception area, the rule inspects the From address for email addresses or domains of allowed senders.
The rule has run out of space and I cannot add more addresses/domains. There must be a better way. I need some direction.