There should be a switch that allows us to make the technician you're able to select dependent on the Group the ticket is assigned to. For example, if I have a Network group with John, Jane, and Joe as members, when I change the Group Assignment of a ticket to that Network group, I should only be able to select John, Jane, or Joe in the Assigned to field. Technicians that aren't in the assigned group should not be able to have the ticket assigned to them.