Hello @MichaelS24. This is possible, we do something very similar. It takes writing a script that hides all items leaving only the categories that you want visible. What we do is we have categories that hold various service items that are in draft status that are not visible to requesters, then we move the service items into published status and a visible category for our users to browse to.

Here is an example of hiding the individual service items. This is placed in the “Page Layout” section that can be found under Helpdesk Rebranding > Portal Customization > Layouts and Pages > Portal Layout

<script type = "text/javascript">
  if (window.location.href.endsWith("support/catalog/items")) {
    jQuery("#catalog_items_container").hide();
    jQuery("<h3>Please select from one of the categories on the left.</h3>").insertAfter("#catalog_items_container");
    jQuery("#categories").click(function () {
      jQuery("#catalog_items_container").show();
      jQuery('h3:contains(Please select from one of the categories on the left.)').hide();
    });
    jQuery('#catalog_search').keypress(function (e) {
      if ((jQuery('#catalog_search').val().length > 0) && (e.which == 13)) {
        jQuery("#catalog_items_container").show();
        jQuery('h3:contains(Please select from one of the categories on the left.)').hide();
      }
    });
  } 
  </script>

And then you can use this snippet to hide categories that you don’t want visible

<script>
  jQuery(" data-id='"+13000064493+"']").hide();
  jQuery(" data-id='"+13000154048+"']").hide();
  jQuery(" data-id='"+13000152827+"']").hide();
  jQuery(" data-id='"+13000154178+"']").hide();
</script>

The number is the ID of the category that you can get by navigating to the category in the portal and grabbing the id from the url.

Hope this helps!