Depending on the system there is combiners and separators to use on a single line if your going to use dish network equip.
some of the receivers that have the hard drive for recording will either require the latter or 2 lines ran to that room.
any how its best to run 4 lines from the dish to a central location where the home runs from all the rooms would come too also.
What type of system are you installing and how many receivers. Direct TV is another story.
