Hide already purchased products (or allow purchasing the product only once) I have a view with a list of product displays, and I would like to hide all the products that are already purchased by the current user. This would allow purchasing products only once per user.

I've tried to modify the view and add a relationship with the order, but I can't find the relationship "Order".
As explained in the similar issue http://drupal.org/node/1221372 , I also tried to create a view of "Commerce Order". I think this would work for displaying a list of purchased products, but not for displaying a list of non-purchased products, because a view of 'Commerce Order' displays results with orders, not results without orders.

Can anyone help me? :)
I would use Content Access to restrict access to nodes by role, then I would make a special role that is required for viewing this product. Then I would create a Rule where buying that product triggers that  role being removed from the user.