Controlling Grouped Speakers Volume?

[motoridersd]

Is there a way to have the Media Hook control the volume of all grouped speakers? The Mini Media Player has a sync_volume option, along with an offset, for grouped speakers. If I use the slider in the card, the volume of both (in my case, but could be any number of speakers) gets changed at the same time. With these blueprints, the target is a single speaker, so changing the volume with the controller (the IKEA rotary in my case) only changes the volume of the target speaker.

Is there a way to edit the hook to target the group? Or do I maybe need a separate automation that tracks a change in the target speaker and adjusts the volume of other grouped speakers only if grouped and playing?