Searching and Updating a Multi-dimensional array

Question

I've searched through all the posts here and can't seem to find the right method to do what I need.

I have a multi-dimensional array of products pulled from a db, via individual orders.

$products = array ();

$i = count ($products);

foreach ($orders as $order):
$res = mysql_query ("SELECT * FROM orders_products AS op LEFT JOIN orders_products_attributes AS opa ON op.orders_products_id = opa.orders_products_id WHERE op.orders_id = '$order'");
while ($row = mysql_fetch_array ($res)):
    $products[$i] = array (
        "model"     => $row['products_model'],
        "name"      => $row['products_name'],
        "option"    => $row['products_options_values'] ?  $row['products_options_values'] : "N/A",
        "qty"       => (int)$row['products_quantity']
    );
    $i++;
endwhile;
endforeach;

Some products have multiple options ie color or box size etc.

I need to create a new array which contains entries for each product according to option and updates the quantities where the option is the same from the existing products array.

This is what I'm trying but I can't seem to get it right.

$items = array ();

$j = count ($items);

foreach ($products as $product):
      $exists = searchSubArray ($items, "model", $product['model']);
      if ($exists and ($exists['option'] == $product['option'])):
        // no matter what I do here I get either all the products, or
        // products without new quantities
      else:
        $items[$j] = array (
        "model" => $product['model'],
        "name" => $product['name'],
        "option" => $product['option'],
        "qty" => $product['qty']
        );
      endif;
$j++;
endforeach;

And here is the searchSubArray function that I came across while searching here for an answer to this.

function searchSubArray (Array $array, $key, $value) {   
    foreach ($array as $subarray): 
        if (isset ($subarray[$key]) && $subarray[$key] == $value)
          return $subarray;       
    endforeach;
}

Any suggestion on how I might implement this?