How to set a Group to 'on' if somebody is at zone.home?

Configuration
1

I created a simply group to check if there is somebody at home, or nobody:

family:
  name: Family Devices
  entities:
    - device_tracker.husband
    - device_tracker.wife

I nobody is at home, the group switches to not_home. If at least one is at home, the group switches to home

So far so good, but how can I let the group be shown as on in the dashboard if anybody is at home? Because currently, the groups is shown as off.

2

This functionality might be better handled with a template sensor. I think there is an example of exactly this in the template docs.