I am working on the same thing right now and just finally got it working. Basically what you need to do is setup a PUB/SUB server to relay the websocket messages to all the nodes, for this I used Redis. I had to create an event gateway to make this happen. I need to test it further but when I am done testing and cleaning up the code I plan to make it open source so that it can help others.
I ported this project over to Lucee and made several modifications
Here is more information