This is a Zendesk Classic widget that will hide ticket fields and then only show them with the agent is part of a allowed group list

hide-fields-on-group.js

jQuery(document).ready(function() {

//list of fields to hide
var options = ['#ticket_fields_139051'];

//groups allowed to see the fields 
var allowGroups = [88054];

//function to hide a array of arrays 
       var hide = function(){
           $j.each(arguments, function(i, item){
               for(y = 0; y < item.length; y++){
                  $j(item[y]).parent().hide();
               }
           }
               );
       }
       //function to show a array of arrays
       var show = function(){
              $j.each(arguments, function(i, item){
                  for(y = 0; y < item.length; y++){
                   $j(item[y]).parent().show();
                  }
              }
                  );
       }
//hide the fields 
hide(options)
//get the current users groups and show the fields if the user is in the allowed groups
$j.getJSON('/' + currentUser.version, function(data){
  _.each(data.groups, function(x){
    var inArr = _.contains(allowGroups, x.id);
    if(inArr) {
     show(options);
    }

  });

});

});