How to send all incoming mails to other local mailserver

Hi,

I'm trying out exim and run into a little problem.

Now, Exim accept incoming mails after auth and send it directly to
destination mail server. In normal way it's ok, but I must send ALL
incoming mails on exim to an other local installed mailserver. Nothing else.

Is there anybody who can tell me how can I do this?

thanks
Ralf