[otrs] Ticket state depending of ticketfreetime fields

Hi, Would it be possible to create a genericAgent job that changes the state of a ticket depending of what is in a ticketfreetime field? My idea is that when a ticket is created, our staff must provide the customer with an ETA. However, in the customer interface, there is now way to see this field in the overview interface. So if I could make a job that does: If ETA < $CURRENTDATE and Ticket State is not closed, then Change Ticket State to "ETA expired". Thanks, Ugo