Advanced Reference Qualifier Using a Script Include ServiceNow

javascript: new getDepartment().getDepartmentUsers(current.variables.caller_id);

Script Include Function:

getDepartmentUsers: function(department) {
 var usersList = [];
var grUser = new GlideRecord('sys_user');
 grUser.addQuery('department', department);
grUser.query();
 while(grUser.next()) {
usersList.push(grUser.getUniqueValue());
}
 return 'sys_idIN' + usersList;
 },