Don't know if this topic is still active. But my 5 cents idea is:
1. Client side replication is open to uncontrollable issues
2. Replication / Message passing must be done on server side
I thought and tried following scenario
1. Put N servers in round robin DNS, which will be good for HA
2. When a server gets message, it will propagate it to N-1 servers (tried that with nodejs listener, with channel listener), works great.
Still not sure if this is the right way or not, actually rather than nodejs listener, it will be great to have a directive on nginx, which pushes the message to a logger/listener etc