Go to THIS WEBSITE and see if this solves your problem.

Thank you, gilloz, that would do the trick. But, I was trying to avoid running more cables since the direct tv ones are already run to every tv. If I could get the box to carry the dvd signal, I would avoid having to run more cable as the space is rather large.

OK. I am trying to picture your setup. I am assuming you have one Dish antenna feeding 4 HD Direct boxes, is that right?
I thought that the Direct TV required one LNA/LNB per box. Is there a TIVO in this mix at all? When you say an HD box, are we talking about a Direct TV receiver? I was trying to draw a block diagram of your setup to get a better understanding of what it is you have in your setup. Set me straight here.