Under Win32 there is an API SetProcessAffinityMask() that allows you to restrict which processor(s) a process can run on. There seems to be a similar call (SetAffinityMask()) on some versions of Linux also.

You would need to write a small command line utility to start the program, get the process handle (probably pid under Linux) and apply the call to it. There may even be existing utilities out there to do this for you.