one machine for recipient address_verify, another for delivery

[lconrad]

outbound flow
first machine does reject_unverified_recipient, and sends verified 
recipients via relayhost to the 2nd machine for delivery of verified 
recipients.

now we see reject_unverified_recipient is verifying through the 
relayhost

is there a way to override the first machine's relayhost so its 
recipient address verification is done to Internet with MX lookups?

thanks
Len