[vPostMaster] commercial server-level spam filtering that works with vpostmaster?

[Wallace Winfrey]

Hello

I'm wondering if anyone can tell me if there are commercial spam 
filtering services that will work with vpostmaster?

We're quite happy with our vpostmaster install, but since about Sept of 
last year, the load that running spamassassin and clamav places on our 
server has slowly risen to unacceptable levels, and it's having a 
negative impact on the rest of the services we run on our machine.

Our organization is very interested in offloading this process while 
still hosting our own email. Is this possible? Someone in our company 
recommended mxlogic but they seem like a complete mail service.

Any suggestions would be most welcome.

cheers

w