Mini-media-player Sonos volume sliders

I am setting up my Sonos card. So far it is coming along really well.
The problem is that I cannot see individual volume sliders for all the zones in the group. I do see screenshots in the forums where this is possible but I cannot seem to get it to work.
Any ideas?

type: custom:mini-media-player
entity: media_player.russound_4
group: true
  power: true
  icon: true
  source: true
  platform: sonos
  show_group_count: true
    - entity_id: media_player.russound_4
      name: Russound
      group: true
    - entity_id: media_player.family_room
      name: Family Room
      volume: true
    - entity_id: media_player.game_room
      name: Game Room
      group: true
    - entity_id: media_player.gym_4
      name: Gym
      group: true
    - entity_id: media_player.basement
      name: Basement
      group: true
    - entity_id: media_player.bedroom
      name: Bedroom
      group: true
volume_step: '1'
  columns: 3
    - name: Lite FM
      type: source
      id: 93.9 Lite FM
    - name: 94.7 Classics
      type: source
      id: 94.7 WLS
    - name: Hit List
      type: source
      id: Hit List
    - name: Good Music
      type: source
      id: Just Good Music
    - name: Mega Hits
      type: source
      id: Mega Hit Mix
    - name: Solo Piano
      type: source
      id: New Age Solo Piano
    - name: Party Hits
      type: source
      id: Party Hits
    - name: Pop
      type: source
      id: Pop - TIDAL Masters
    - name: Smooth Jazz
      type: source
      id: Smooth Jazz New York Radio
    - name: Soft Pop Hits
      type: source
      id: Soft Pop Hits
artwork: full-cover

Same problem here. The volume slider only controls the master, not all grouped speakers. Would like to have an option for equal volume over all speakers vs increasing/decreasing volume relatively to each speakers current volume.

Without either it makes it a bit useless though.