This is what I would try.
3 TVs (Room 1 - Fake TV)(Room 2 - Fake TV)(Hidden Room - Real TV)
A fake generic HDMI splitter. NVX Rx HDMI to splitter, splitter to all 3 TVs.
Room 1 programming.
Add an if statement under Room 1 -> Media Events -> TV On, if Room 2 -> TV -> Media Operations -> Is On = Ture, then Room 2 -> Media Operations -> Room Off.
Add an if statement under Room 1 -> Media Events -> TV Off, if Room 2 -> TV -> Media Operations -> is On = False, then Hidden Room -> Media Operations -> Room Off. - This will shut off the TV.
For each source you will need to put an if statement under Media Zone Events -> Video Source Changed. That if will look something like this, If Room 1 -> Media Operations -> Video Source = Apple TV, then Hidden Room -> Media Operations -> Router -> Apple TV.
Room 2 programming.
Add an if statement under Room 2 -> Media Events -> TV On, if Room 1 -> TV -> Media Operations -> Is On = Ture, then Room 1 -> Media Operations -> Room Off.
Add an if statement under Room 2 -> Media Events -> TV Off, if Room 1 -> TV -> Media Operations -> is On = False, then Hidden Room -> Media Operations -> Room Off. - This will shut off the TV.
For each source you will need to put an if statement under Media Zone Events -> Video Source Changed. That if will look something like this, If Room 2 -> Media Operations -> Video Source = Apple TV, then Hidden Room, -> Media Operations -> Router -> Apple TV.