Inbound Email Configuration

We have a situation here. We have 2 systems on one physical host. Both are NW 2004s SP13 systems with MSSQL database. We have configured inbound email for both these systems for SMTP port 25000 and 25001. However when we send inbound email to system2, its reaching inbound of system1. Inbound emails to system1 are getting delivered correctly delivered to system1. I am not sure whether this is something controlled at exchange server end on the relay (our Microsoft Exchange is 2007 version). Sapnote 455140 says i have to configure virtual host only if more than one client exists and I want all incoming to be routed to single client. This note is not applicable in my case. Just wondering if you have any advise

Regards

Kal