Oh boy. There's a lot to unpack in your post. First off, the Beo4 is not very good for use with a matrix. The BeoRemote 1 is much better as it only requires a single button press. Better still, you can assign Matrix 1, Matrix 2, Matrix 3, and Matrix 4 to MyButtons.

I went through the daunting task of running Cat7 cables for an Atlona matrix for distribution to my Beosystem 4, 2x BeoSystem 3s, and a BeoVision 10. It looks weeks to get it working properly. Mostly because of the difficulty getting the correct optocouplers and getting the Atlona hardware to work properly. Sometimes, I still have to power cycle the Atlona matrix to get things working correctly.

My realization is that a similar result could be achieved just by connecting an Apple TV to each of the TVs. The Apple TVs stay in sync so that you can pick up from one tv where you left off on another tv.

My dealer told me that the keys usually cost around $700 or $800. He was kind enough to unlock mine at no charge, though.

Gary Nelson wrote:

To do this I expect to have to buy a "key" from B&O for this luxury - any ideas what this costs?

Does anyone know how I can obtain an HDMI feature activation key for the beoplay v1? My dealer couldn't find any information on this. Have the new opto-coupler all ready but can't use it! Many thanks, Rob.