Is there a device that can interrupt a live cable feed to run company related commercials?

Answer 1

This would be difficult to do. If you know what channel is being watched, you could use an A/B switch and an RF modulator to broadcast whatever you want whenever you want on that channel but only that channel. There are devices that you can modify TV's with that will force tune a TV to a specific channel on command or turn them on or off, but all of the TV's you wanted to control would have to be modified in this manner or all new TV's to be purchased.