Mail Merging Multiple Objects Please Help :)

Hi Guys

I am Doing some research on mail merging from multiple objects and am wondering if this is possible and how it is done, what I need to do is mail merge from my company screen opportunities screen and a custom object which is going to be a rate card, I though whilst I research my answer I ask on here as well in case there is a quick "No it can’t be done" or a "Yes" which would be nice. I have just only started my research and have read something about linking the objects via a related list, has anyone else had to do anything like this before, any feedback would be greatly appreciated J

Thanks

James