[Exim] pull back lookup info as variable

This is a multi-part message in MIME format.
--
[ Picked text/plain from multipart/alternative ]
Does anyone know how to pull back the result of a lookup in a router so you can run a condition based on the ip the lookup gets back??

I cant seem any info on the site or book about it but may not be looking in the right area.

I need to lookup stuff based on domain name and depending on the MX ip address it gets back i need the router to pass or fail so it can go to transport or onto the next router. I am required to route mails to different locations depending on the ip address of the MX record for domains. I cannot determine and list all the domains see as they are unknown, but the ip address range is known.

Please help

Thanks
Dave
--