adding third hd dvr

i have a slimline 3 the lnb is sl3pig3, i have 2 rg6 cables to the first hr-22 in one room and 2 cables run to the other side of the house connecting to the second hr-22, i want to add a third hr-22 one the other side of the wall from the second hr-22, how can i make those 2 cables work 2 hr-22, multi switch, splitter, thanks can you help me