SMTP Proxy

I am looking for a SMTP proxy that simply verifies that the intended inbound email recipient is actually a valid recipient (email address).
I am running a trend micro spam/anti-virus filter before my exchange 55 server, and the Trend product has no facility for just binning the messages intended for fake addresses.

For Example: message to fakename@mycompany.com > binned.

validname@mycompany.com > passed to Trend Spam/AV filter > passed to Exchange server.

The reason I am looking for this is to cut down on the quantity of messages that are in quarantine, cut down on processing time (at the spam/av filter), and generally improve email performance.

Is this even possible in a Win environment?

Thanks,
Chad