RT 3.8 - Queues user permissions


I have a queue called “Entrance” and i want the helpdesk team to analise the ticket and then change it for the corresponding support queue.

Two questions:

        1 - I want helpdesk team to have permissions to change the queue ticket and so they must have "Showqueues" permission but i dont want them to open the support queue. Is this possible?

        2 - I want that, when the helpdesk team change the ticket queue and if a specified "custom filed" isnt filled, RT 3.8 gives an error to the user and the queue change operation isnt performed. Any script to do that? How do i show error messages to the users from script ?

Another question:

How can i run some daily based scripts to perform some actions in RT. RT 3.8 have a “crontable” tool? If yes how can i configure it?