Hello,
Why are you trying to operate across domains in the same DMQ cluster? Usually, servers operating in different domains do not need to be aware of each other's user location and/or subscription records - if a request is for another domain, simply forward it to the server(s) responsible for that domain.
Also, regardless of DMQ or any replication, publishes for one domain would not match subscriptions for another domain; even on a single server.
Can you describe your architecture in more detail and what you are looking to achieve with replication?
Cheers,
Charles