Create a client like this to connect to the Process Server
private static TaskClient client = new TaskClient(new MinaTaskClientConnector("client 1", new MinaTaskClientHandler(SystemEventListenerFactory.getSystemEventListener())));
Connect like this
client.connect(taskServerIP,taskServerPort);
And add a task like this
client.addTask(task, null, addTaskResponseHandler);
the task object will contain information about PotentialOweners who can be User or Groups(which is your case)
Regards,
Franklin