Excluding agents from tasks

[Ulagapiragasam Vanathy (RBAU/ISY)]

Can we exclude an agent from a specific task?
 
For example:
 
Task 1 work item can be executed by agents who hold Job1. Where
Job one contains Positions Pos1, Pos2 & Pos3.
 
Job 1 --->  Pos 1,
                  Pos 2,
                  Pos 3.
 
 
All I need to is exclude Pos 3 from executing the task.
 
Thanks in Advance
 
Vanathy