I have an older standard defenition dish (18" Round & 2 LNB's) that I am using with R-22, R-15 and an old RCA receiver. Right now I am using two multiswitches cascaded to provide inputs for the units. The R-22's have and input for a SWM. I plan to replace the old RCA with another R-22. Can I replace the multiswitches and use a SWM in its place and use the legacy ports to run the R-15.