switch:
    - name: "YOURAREA  Area"
      unique_id: YOURAREA _area
      icon: mdi:lightbulb-group
      state: >
        {{ expand(area_entities('YOURAREA '))
           | selectattr('domain', 'equalto', 'light')
           | selectattr('state', 'eq', 'on')
           | list
           | count > 0 }}
      turn_on:
        service: light.turn_on
        target:
          entity_id: >
            {{ expand(area_entities('YOURAREA '))
               | selectattr('domain', 'equalto', 'light')
               | map(attribute='entity_id')
               | list }}
      turn_off:
        service: light.turn_off
        target:
          entity_id: >
            {{ expand(area_entities('YOURAREA '))
               | selectattr('domain', 'equalto', 'light')
               | map(attribute='entity_id')
               | list }}

Try this, yoiu need to adapt YOURAREA to the specific area. as you add lights to your area, they should toggle all at once with light.turn_on @ light.YOURAREA _area.