You can see what friends have scheduled to join a group ride or race in Companion app. With 500+ friends connected almost all sessions in the schedule show I have one or more friends joining.
If I would like to join a specific friend on a scheduled ride it is almost impossible to find. Would be great to go the other way around. As you can see on a friend profile the past activities it would be nice to be able to see what sessions the friend has scheduled and directly schedule to join the same ride.