[DrQuietus]

Slight amendment, to avoid more category loops:

<table>
{section name=cat_num loop=$product_links}
{assign var='i' value=$u_product_info[cat_num].categoryid}
{if $i ne $n}
  {foreach from=$categories_menu_list item=c name=categories}
  {if $c.categoryid eq $i}
   <tr>
     <th colspan="3">{$c.category}</th>
  </tr>
  {assign var='n' value=$c.categoryid}
  {/if}
  {/foreach}
{/if}
<tr>
-----UPSELLING PRODUCTS-----
</tr>
{/section}
</table>