Does anyone know how to install exchange server 2003 standard into an RM CC3 network.

I have 3 DC's and two member servers one of which will host my exchange 2003 code.

I am not sure how to go about installing exchange 2003 on the member server without affecting
the current operation of cc3. I know you can purchase exchange 2003 from RM who will integrate it
at a cost but I was trying to avoid that.

Thanks in antisipation.