[exim] SMTP delivery question

Hello.
I'd like to ask about a solution for my problem.

The point is that our provider didn't delegate us our reverse DNS zone
(in fact he asks much money for this), so sometimes there are problems
delivering mail from us to the Internet...

I would like to know whether it is possible to configure Exim to try to
deliver the message and if there is an arror, try it again, but using a
different router (that will do it via another SMTP-server, which is
quite cheaper than delegating a reverse zone).
How should I configure the routers for this?..
My first router is dnslookup with default configuration.
How should I configure the second router, which will work via another
SMTP-server only if there has been an error?


Thanks for any suggestions.




--
Best regards,
Danil V. Gerun.