[Exim] exim setup

Hello,

I require some help on a solution with exim 4. Basically I will
have 2 smtp servers.. The one is hosted onsite the other offsite..

Both SMTP servers serve mics.co.za. (MX goes to offsite server). All mail
for that specific domain (domainlist stored in a mysql db.. dont worry
about mysql parts). Will first be checked if it can do a local delivery.
If it fails it must automatically route to a specific smtp server (if the
domain is in a domainlist). Then only if that server fails it must sent
the reciepient the error message.

Basically a quick drawing:

[incoming email]
     |
     |
[check if it can deliver locally -- possibly end of delivery]
     |
     |
[if not, smart route email to a single remote smtp server.. if reciepient domain is in mysql database]
     |
     |
[end of delivery]

Any help would be very appreciated.


Thanks,
Mark