To get all the other product group data on the page, this was included:
$query_products2 = sprintf("SELECT * FROM ps4_products WHERE ProductGroup = %s", $product_group);
$products2 = mysql_query($query_products2, $mmsstore) or die(mysql_error());
$row_products2 = mysql_fetch_assoc($products2);
$totalRows_products2 = mysql_num_rows($products2);
so with that logic, wouldn't
WHERE ProductGroup = %s
have to be part of the query?