I have a SWM dish with only one wire from the dish to a grounding block on the outside of the house. The grounding block has four outputs, three are capped and one output goes to a cable going through the wall to a power inserter. The cable from the PI goes to the SAT 1 input on my hr21 700 receiver. If I order a second receiver and want to set it up for MRV and internet would I need three DECAs? One DECA behind the first receiver after the power inserter. One DECA behind the second receiver (without a PI). The third DECA at my router with its own PI. Also would the RG6 cables come from the gounding block or would I use a switch? And if I need a switch where in this setup would it be located? The router is located in a room separate from the receivers. Cat5 wiring is not available but there is RG6 cable available in all rooms.