Hi wqe(seems it is not your real name),
Thanks for your reply. Just have a quick check about the doc in http://docs.jboss.org/jbpm/v5.3/javadocs/org/jbpm/task/service/UserGroupCallback.html. Actually, it is very hard for me to understand the inner logic and implement an code for UserGroupCallback Object. Would you pls drop me an example or a useful link? :)