Thank you for the reply.
I have googled extensively. Enough to know that there is no non-commercial solution available for this problem. There is a $20 solution called Chameleon which will do exactly what I need, but this seems like an easy issue to overcome without using a third party component. Making a hidden menu for 100's of articles isn't really a solution. Its a very time consuming work-around. Once again, my question is this:
I don't think there is a built in way to do this, but it seems like it would just be doing something like "if catid = x, then url = url + &itemid=y "
My question is, is that feasible and if so, which file should I be hacking?
I know I will no doubt get some protest about hacking the core, but since I am using domain redirects in the index.php, I've already gone down this path.