Trigger variables in automation actions

Hi!
i have a problem with Trigger variables. when i try to set up trigger to group of sensors, i cant receive target entity that triggered.

Group:

windows:
      name: Windows
      view: no
      icon: mdi:access-point-network
      entities:
        - binary_sensor.door_window_sensor_158d0001d68810
        - binary_sensor.door_window_sensor_158d0001d62fb4
        - binary_sensor.door_window_sensor_158d0001d3ab07
        - binary_sensor.door_window_sensor_158d0001d3aaeb
        - binary_sensor.door_window_sensor_158d0001d3a011

Automation:

- action:
  - service: script.windows_open
    data_template:
      message: '{{ states[trigger.to_state.domain][trigger.to_state.object_id].name }}'
  alias: WindowDoor is changed
  id: '1512665687947'
  trigger:
  - entity_id: group.windows
    from: 'off'
    platform: state
    to: 'on'

The statment always return name of group (Windows)
{{ states[trigger.to_state.domain][trigger.to_state.object_id].name }}

How can i fix it??
Thanks.

add a separate trigger for each window sensor.

thanks, i know this variant