Shopping Cart Sidebox Grouping

Does anyone know how to rearrange the Shopping Cart sidebox so that when I buy my products they will be separated into their subcategories in the sidebox? I see the php file under sideboxes, but I'm not sure how to write the code to group them by category id.

example: I sell cabinets so I want in my shopping cart sidebox for all the base cabinets to be grouped together and all the wall cabinets to be grouped together even if the customer buys a base, then wall, then 2 walls, then 3 bases. I want them to be grouped by their ID.

I'm not sure if the sidebox code has the product's cPath info available, but there is a zen_ function to look up a product id's master category id. You could add that as a new field to the output array, then sort the array contents by the value of that field.

If you can sort by categories_id, products_name for this ... you could customize the file:
/includes/templates/your_template_dir/sideboxes/tpl_shopping_cart.php

and add the code in RED to do this:

    $products = $_SESSION['cart']->get_products();

// bof: sort by master_categories_id and products_name
    function sort_products_category_name($a, $b) {
      $retval = strnatcmp($a['category'], $b['category']);
      if(!$retval) return strnatcmp($a['name'], $b['name']);
        return $retval;
      }

      usort($products, 'sort_products_category_name');
// eof: sort by master_categories_id and products_name

    for ($i=0, $n=sizeof($products); $i<$n; $i++) {