Mail Routing

we have domain name that is bieng used just as URL for our website, we host the website with a company in India, We now want to change our mail domain to the same one as the website domain (they are currently different).

We have a Cisco 3600 router which points to our local ISP and to other routers on the internal network.

We are using Exchange for the mailServer and it is inside the LAN.

What configuration changes and steps do we need to make to route our mail using the domain of the website URL ?