It would work, however the beauty of a single "command" unit is no MU configuration and no getting out of sync with each other. One of the constant issues with TMCC/Legacy MU configurations is a power interruption makes them forget they're in an MU and the revert their direction to "forward".
Yes, you can wire them to run backwards for "forward", but that makes them an oddball.
That being said, it would be possible to just remove the tether and do that. However, I always wanted to do one of these this way, and now I'll have my little board to make it happen.