Is there a way to send a custom attribute to an order that is hidden to the user but viewable by the admin.

This is how the site is currently working. A user selects an item, is directed to a custom made page to customize their ordered item. And is then directed to the regular product_info.php page. I have appended an id to a row in a table saved in the database to the end of this URL. I need this ID to be sent along in the order and in whichever page displays the order details ( in the admin ) I need to grab some values in this table based on that ID and display it to the admin. I realize this is probably some pretty custom stuff but I mostly just need to be directed to the right files so I can get to work.

Thanks,
Nick