CableMaxx a competitor to Paragon Cable San Antonio had such system all TV's had to be hooked up to a Scientific Atlanta Cable box, you got 45 channels, my neighbor used to have it. Two cable lines had to come out of the wall instead of one.
I think Grande took it over, But I still couldn't understand how they did it, since the cable lines were over head, and I didn't see lineman install new pole wiring.
For VCR's not complicated at all, however watching one program while recording another, forget about it as it had to be on Channel 3 or 4. Of course, you could have two boxes which would be 4 incoming cable lines (haven't seen it, but possible)
In 2000 they switched to Direct Broadcast Satellite.