I have 2 tvs runing on a 722k fed by one cable down from the dish. second line down feeds a 311 sd setup. what I want to do is add another 722 and a 222. each one (all) will operate autonomous - like 4 different worlds. can I put a 2 way splitter on each of the down cables and thus feed the receivers ? and how about useing attenuators on the antenna's so when any are recording they dont change any of the other receivers. what db range would I need ?