Using remote to control multiple pairs?

[curban]

I don't think you can. I've written a Shortcut on my phone to achieve controlling multiple devices.

Thanks for sharing. On the phone it's not a problem because there is the app... I have considered making an app on the computer (which is always on) that detects the volume on the master device and then syncs it to the other phantoms, with some delay, then. But I have not made up my mind yet. This would be done with the IP control/http "things".