Hello - I have the Arc plugged into the ERC hdmi port. The Arc works great by itself with my Apple TV remote with turning volume up and down and muting.

I also added two eras to the living room group with the Arc.

when I volume up/down and mute/unmute - it only controls the Arc that is plugged in direct to the TV. It doesn’t control the other Era speakers that are in the same living room group.

How can I get all of the speakers to volume up/down , mute/unmute together when using my TV remote?