Queue access

Hello as I told you before I’m running astercc with FreePBX I have queue ex: 3333 and ten dynamic agents that are logging in it. When user dials 3333*# the system prompt the user to enter his number “Agent login. Please enter your agent number followed by the pound key.” If the user don’t enter his number the system recognise his extension number and automatically log him with his extension. The problem is when the user dials number different from his extension (ex: 123123") the system logs number 123123 in the queue witch is unacceptable. How can I restrict the user to enter only his extension or when he dials 3333*# to log him with his extension directly without prompting him to enter anything ? (Or how can I define allowed users in the queue and the other who are not defined > /dev/null

Thanks is advice !
Emil Kotsev