Someone I know wanted to find out if this scenario would work with Channels DVR: This is an outlier scenario (possibly rare)… but gotta ask… 
They have FIOS themselves and live in a gated/planned community that the HOA has a “forced” cable feed (HOA contract with cableco).
They do not have any tuners or equipment yet other than the fios / cableco dvrs.
With 2 primes, one on the fios and one on the cable feed, would channels DVR work (ie:combine and/or merge [separate RF feeds of course]) the channels and allow recording and playback from both sources but provide a unified interface?
The current recommendation for most in this situation is to use just the fios for both primes to get more tuners… but unfortunately the offerings are different (~20 channels that are on one but not the other each way, with fios having the “better” lineup)