How do I route all mail from one domain name across a Frame connection and everything out our standard internet connection?

I currently have a single exchange 2003 server and I have one Routing Group with one connector and has a * in the address space area of the properties box.  we have a need to take all emails destined for one of our clients example clineta.com and route it across a frame relay connection.  All other mail will contiune to route via the same path only the emails destined for clienta.com will route across the frame line.

The flip side of this is also true their mail server will also be setup to push across the frame connection is there anything I need to do on my Exchange Server for it to accept the mail?

Thanks