I'm a little confused on what I will need. I currently have a dish 500 with 2 legacy dual LNB's and 1 single LNB dish going into a SW64 to 2 dish 6000's. Picking up Sat's 110, 119 and 148. I want to add a PVR921 but don't want to run another line to where the PVR921 is going (in the place of...