This assumes you have one isolated group of friends who communicate mostly with each other and not as much to people outside this group. You would need to convi

This assumes you have one isolated group of friends who communicate mostly with each other and not as much to people outside this group. You would need to convince your friends+family to switch, then they in turn need to convince their other friends+family to switch, and so on. What your friends did is install Signal to communicate with you.