[Exim] smtp-forwarding

Hi,
i want to do some smtp-forwarding with exim. can someone tell me how to
configure exim to forward all mails it gets for a specific domain, let's
say example.com, to another ip-adress (my "hidden" mailserver). on the
other hand exim should forward all mails from my "hidden" mailserver to
all internet-domains, but should only accept incoming connections from
my "hidden" mailserver (if the destination is everything but the
example.com domain). there should be no local user on the exim machine,
just forwarding in both directions. how can i shut down local mail
delivery, or should i?

i thought about using:
relay_domains = *.example.com

and for outgoing mails:
host_accept_relay = 192.168.1.1 (my "hidden" ms, f.e.)

is that correct, what should i take care of?

please help, thanks
daniel