[Exim] bouncing mailer deamon messages on secondary mx where…

Here's the situation: A spammer out on the net, most likely from multiple
DSL accounts, sent spam to a bunch of unknown address with the from address
being vlad@???. Since I administer the primary and secondary mx for
ohwy.com, I got all the bounce messages stuck in the queue. So, I started
doing recipient verification on my primary mx (where the pop3 accounts are
physically located). Now, my queue on my primary doesn't get filled up.

Now the problem is with my secondary MX. If the bounce from the spam hits
my secondary mx first, my secondary mx accpets it, and relays it to my
primary. My primary gives a "user unknown" message and my secondary keeps
it in the queue.

How do I do recipient verification on my secondary so that I can only accept
the message if the recipient address really exists?

Sincerely,

Rick Duvall
Online Highways
System Administrator
(541) 997-8401 x 111