Thank you for your reply :)
As you said Rudolf Michael, i can create candidate-groups but when more than one user submit the application then for each processInstance user will have only cancellation as task list but admin should have all the the processInstances for all submitted application.. how should i have to do this?
But here i have display the same Task in the Admin User list as well as for User list also for he same processInstance that was started by submitting the application by normal user but with different name as:
in Admin ------ Assignee To and in the User ----- Cancellation , at same point of time.