I've been trying to figure this out for a little while now, and if I extend your tutorial to have one addition node, then I cannot get everything to work. Say I have master, client1, and client2.
I can get master to talk to any of them. I can get client* to talk to master. But I cannot get client1 to talk to client2 or vice versa. Even if I add in client1 a ConnectTo=client2.