I just ordered DirecTV and after I hit the "Buy" button I thought of some things that I wish I'd have thought of beforehand. First of all, AFTER ordering, I discovered that my local channels are NOT available in HD in my area. However I do have an attic antenna that picks them up just fine. So I'm assuming that the installer could use diplexers to give me access to both the DirecTV dish and the attic antenna, right? Now for the complicated part: I also have a FTA dish that I want to continue using. Is there such thing as a "triplexer" that will give me access to all three sources? If so, is it likely the installer would have them on hand?