postfix mail as Spam issue.

Frist of, This problem only happens when the domains are on the same VM server...

When joe@domaina.com sends an email to mike@domainb.com (both on the same VM server)

The headers says the email is from the local(email user)machine and includes the IP of the gateway they are going thru. Therefore, emails to domains on the same server can get classified as spam if they are in DUL like SORBS... ETC.

Is there anyways to bypass all domains on the server from spamassassin?