[otrs] Setting default TO: field in customer ticket

Hi all, I modified some of the Customer Interface settings (only viewing the "external" queues in the New Ticket interface of the customer), which all succeeeded, but I'm looking to set 1 default queue. For the moment, I have the "new ticket" page with a dropdown TO: field. I'd like to replace the standard "-" by the first entry in the list (or something else) Regards, C.