In a Windchill cluster environment, the master node is the node which runs the master cache server manager. This server manager synchronizes caches between all nodes of the cluster. Only one server manager can act as the cache master at any given time, so you can't have multiple master nodes. But, you can absolutely split your queues between multiple nodes. What you could do is have one master node which runs a BGMS that handles all the non-workflow queues, one slave node that handles user requests, and then third background node that doesn't handle user requests, but just runs a BGMS that handles the workflow queues. This node would be set up the same way as a slave node. But, in the wt.properties file, you'd configure it not to start any Method Servers, and instead just start a BGMS process configured to run the workflow queue group.