Notification if someone out of the group starts live tracking?

[bongo]

we have a private group for live tracking.
is there a way to get notified as soon as someone starts live tracking?
the idea is, that the others of the group get informed as soon as one goes to a trip. so this allows to start a search if you recognize that someone got lost somewhere or had an accident in the mountains. but if you don't even know that someone went to a trip, you don't know that you should track him...