Multi-channel RF moderator

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I was thinking that since the FCC is soon going to shutdown the NTSC, all of are TV's is only going to be set to channel 3. I thought that was a little wasteful, so I was wondering if there was a device that can transmit a signal from multiple device's to other channels instead of 3.

For example, to access a DVD, VCR or a converter box, they would connect to a multi-channel moderator that would transmit the devices individually on CH3, 4, and 5; So to view them you would simply change the channel on your TV.

So is there such a thing as a multi-channel RF moderator? Or that can only be done through the airwaves.