Whole house audio with Chrome cast

Im trying to create a whole house audio setup with chromecast, Id like to be able to play to my 3 chromecast devices simultaneously but also be able to independently control the volume of each room from a button on the wall.

Ive got the chromecasts setup in a group to all play together which works great, however i cant workout how to do individual volume control except through the google home app on my phone.

Anyone have any ideas?

I’d say that in addition to your group of media players you also have to add the individual media player entities for each Chromecast to your view.

Sorry i should have mentioned, all of my chromecasts and the all group are detected as separate media entities in HA.

when playing to the group the other chromecasts are inactive in HA

I have the same. I think if you set up the volume of each CC first, when you cast to the group, each entity will retain its volume level, unless you set a volume for the group.
If you set a volume for the group, each CC gets assigned the same level as the group.
Not sure there’s a way to adjust the volume of each CC once you’ve started to cast to a group…

Ive sorted part of my problem out, Turns out you can still set the individual chrome cast audios volume with the media_player.volume_set service

Now i just need to work out how i can create an input slider to set the volume and then create a volume nob for each room

this is an extract from my config, amended but I think it should work, or at least set you on your way:

    name: Volume
    icon: mdi:volume-high
    initial: 0.4
    min: 0
    max: 1
    step: 0.05


  - alias: Set Chromecast Radio Volume
      platform: state
      entity_id: input_number.volume_radio
      service: media_player.volume_set
        entity_id: media_player.bedroom
        volume_level: '{{  states.input_number.volume_radio.state  }}'