I had an issue where i have an All On/Off Central group address in KNX but I didn't want to be able to do a Switch On All for a switch from Home Assistant.

I came up with a template switch like this:

knx:
   switch:
      - name: 'Alles Uit/Aan'
        address: '0/0/1'
switch:
 - platform: template
   switches:
     alles_uit:
       friendly_name: "Alles Uit"
       value_template: "{{ is_state('switch.alles_uit_aan', 'off') }}"
       turn_on:
         service: switch.turn_off
         data:
           entity_id: switch.alles_uit_aan
       turn_off:
         service: switch.turn_off
         data:
           entity_id: switch.alles_uit_aan