smart router with verification

[bigdessert]

We have a smart router setup like this in two parts:

smart_route:
driver = manualroute
route_data = ${lookup{$domain}lsearch{/etc/staticroutes}}
transport = remote_smtp_smart

second part:

remote_smtp_smart:
driver = smtp
port = 26
hosts = ${lookup{$domain}lsearch{/etc/staticroutes}}
hosts_override

We have in the staticroutes localdomain.com: remote server ip
And have 3 domains being forwarded.

What I am trying to do, setup a flat file with email addresses and do some sort of recipient verification on it.
I am a newb when it comes to exim, so if I could please have some direction.
Thanks!

[bigdessert]

figured it out added this condition line

smart_route:
driver = manualroute
route_data = ${lookup{$domain}lsearch{/etc/staticroutes}}
condition = ${lookup {$local_part} lsearch {/etc/specificusers}{yes}{no}}
transport = remote_smtp_smart