Add a device group to a topic in Firebase?

Question

Its possible to add a device token to a topic, and it's possible to add a device token to a device group, but is it possible to add a device group to a topic? It would seem sensible to do this but I don't see any reference to it in the new Firebase docs?

Answer 1

I got a response from Google/Firebase that this is not possible, which seems a shame as it looks like a reasonable thing to do...