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 v1.0.0

    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

mode: queued
max_exceeded: silent

variables:
  linked_entities: !input 'linked_entities'

trigger:
- platform: state
  entity_id: !input 'linked_entities'

condition:
- condition: template
  value_template: '{{ trigger.to_state.state != trigger.from_state.state }}'
- 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) }}'

action:
- service: homeassistant.turn_{{ trigger.to_state.state }}
  target:
    entity_id: '{{ expand(linked_entities) | selectattr("entity_id", "!=", trigger.entity_id) | map(attribute="entity_id") | list }}'

I have an idea/feature request. One of the lights that I sync using this blueprint is connected to a conventional wall switch. When I turn off the switch, the light goes to Unavailable status.

It would be great if there were a selection option in the setup for the blueprint to set the behavior if one of the synced objects goes unavailable. I'm thinking three options:

• Turn all off
• Turn all on
• Do nothing

I'd give it a try myself but I'm not familiar enough with blueprints to be confident with it.

Hi, I'm trying out this blueprint. It works most of the times. Testing out with two switches. The failure scenario:

1. Manually turn on Light 1
2. Light 2 turns on
3. Within 3 seconds turn off Light 2
4. Light 1 stays turns on.
5. HA dashboard always reflects the correct state.
   NOTE: If I wait longer then the automations would work.

How can I debug this?
I noticed the same behavior with a very similar automation that uses mode: restart mode.