I have a single LNB dish from DirecTV with a multi-switch enabling me to feed signal to two televisions (with individual receivers) and one television with TIVO receiver. I want to upgrade to HDTV on one television but only when I can record HDTV programming to watch at a later time. Should I wait for the new R-921 receiver? Can I then get one superdish to replace the current DirecTV one? My building will not allow more than one dish. If I decide in the future to have HDTV sets in all three rooms, will I need upgraded receivers?