Mail Server Backup/Forwarder to Alternate Port

[mdowner564]

My Plesk 9.3.0 Server is at the colo with no port restrictions. I am running an Exchange 2007 Server that is at a residential location and thus opted for the lessor cost Comcast residential circuit. This has been fine for almost 2 years, then suddenly Comcast blocked the inbound SMTP port 25. I have about 40 low use domains on my Exchange server so can't see paying $50yr per domain for a mail server port redirection service. Since I already use the Plesk sever as the DNS server, is there an easy way to capture the mail on the Plesk server, then have it delivered via port 587 (Or anything other than the bocked port 25). I don't want to modify the Plesk Server in a way that will cause issues down the road when doing panel updates/upgrades.

Has anyone attempted this successfully?

Thanks in Advance!