This pull request extends hide_if configuration schema to optionally allow for using the named entity's state/attribute when evaluating criteria for showing/hiding the entity, instead of using the entity's own state/attribute.

Example

  - type: custom:multiple-entity-row
    entity: switch.dsc_armed_away
    toggle: true
    entities:
      - entity: sensor.dsc_exit_state
        hide_if:
          entity: switch.dsc_armed_away
          value: 'off'

Alarm exit state sensor's value (sensor.dsc_exit_state) will be displayed only when the alarm is armed (switch switch.dsc_armed_away is ON).