We already have a cache cluster which uses Gemfire Locking to conflicting work in Synchronous manner but now we need a third cache client/cache peer which will have data but should not participate in Gemfire Locking but have all the latest data which will be used by a external UI application to show data on UI. New Gemfire Client/Peer will reside in UI application.
You could do this by making the 3rd server be its own separate distributed system connected with the original via gateways ( http://gemfire.docs.pivotal.io/latest/userguide/index.html#topologies_and_comm/topology_concepts/how_multisite_systems_work.html ). This would provide reliable, asynchronous replication to the third server.
If the UI has sufficient space to accommodate the whole data set, an even simpler solution would be to use the local cache capability with interest registration ( http://gemfire.docs.pivotal.io/latest/userguide/index.html#developing/events/configure_client_server_event_messaging.html). This would push all of the changes into the UI asynchronously.