User accounts can be added to one or more groups that are configured on the network operating systems as well. These can be set by whatever rules the network administrator decides; of course, in schools, teachers are often assigned to groups based on the subject areas taught and grade levels taught, so they will be able to see and access files of importance for responsibilities, but not to others. Groups are often set by other criteria. For example, by adding only those teachers who have been training in using the 3-D printer to the group allowed to use it, network administrators can prevent its misuse.