Select multiple entities to link their on/off state. If any selected entity is turned on or off, the other selected entities will be sent a matching on or off command.

link_multiple_devices.yaml

blueprint:
  name: Link On/Off State of Multiple Devices
  description: '## Link On/Off State of Multiple Devices v1.0.4

    Select multiple entities to link their on/off state. If any selected entity is
    turned on or off, the other selected entities will be sent a matching on or off
    command.


    You can select any entity, but only entities supported by the `homeassistant.turn_on`
    or `homeassistant.turn_off` service calls will work.

    ### Requirements

    * All selected entities MUST suport `homeassistant.turn_on` and `homeassistant.turn_off`
    or errors will be logged and the blueprint will not work.

    * Requires Home Assistant 2022.5.0 or newer.

    ### Credits

    * [@adchevrier](https://community.home-assistant.io/u/adchevrier) for the [initial
    blueprint](https://community.home-assistant.io/t/synchronize-the-on-off-state-of-2-entities/259010)

    * [@hebus](https://community.home-assistant.io/u/hebus) for [this fantastic template](https://community.home-assistant.io/t/synchronize-the-on-off-state-of-2-entities/259010/38)'
  domain: automation
  homeassistant:
    min_version: 2022.5.0
  input:
    linked_entities:
      name: Entities to link
      selector:
        entity:
          multiple: true
  source_url: https://gist.github.com/dbrand666/b731672b2a282b9afd51a97e6e5c2b2b
mode: single
variables:
  linked_entities: !input linked_entities
triggers:
- trigger: state
  entity_id: !input linked_entities
condition:
- condition: template
  value_template: >
    {{
      (trigger.to_state.state == "on") or
      (trigger.to_state.state == "off")
    }}
- condition: template
  value_template: >
    {{
      trigger.to_state.context.parent_id is none or 
      (
        trigger.to_state.context.id != this.context.id
        and
        trigger.to_state.context.parent_id != this.context.id
      )
    }}
actions:
- action: homeassistant.turn_{{ trigger.to_state.state }}
  target:
    entity_id: >
      {{
        expand(linked_entities)
        | selectattr("entity_id", "!=", trigger.entity_id)
        | map(attribute="entity_id")
        | list
      }}