[Exim] reject-policies -> exim configuration

hey all!

I've been playing around with the configuration for quite a while now, in
order to improve the mail server...

I have a file with senders, that shall be allowed to relay to any domain
through that mail server. Anyways, ... I can't get it working... whatever
I try, it either lets through all mail, or rejects everything but mail
for local_domains.

I guess such a setup is not too uncommon...
Maybe someone can send me his configuration, so that I can sort this out
finally?

Thanks for any help!

-philipp