AbleCommerce Shopping Cart Software

The majority of our products are for sale only for US customers. But we do offer some items for international customers. Is there a way to prohibit the sale of certain items based on the customers location/region/country? Ideally, it would be nice if a customer could only view the items that were available for sale to him/her rather than view our whole catalog (but I would imagine we would need to require a "login" to shop so we could know the customer's country). Instead, having a notation or designation in the product description indicating which region this item is available to would be OK, but it would not prevent someone from trying to purchase the item from an outside area. They could still add the prohibited item to their basket. When they checkout, however, the cart needs to recognize the prohibited item and alert the customer that it not available for purchase and subsequently remove the item from the cart. Any suggestions or ideas on this issue would be appreciated. Thanks in advance

One way to accomplish this could be to make it compulsory to enter country information when new customer try to register. This could be done as suggested in below thread
viewtopic.php?f=42&t=7850

Then you can customize the store display pages showing products to customer to take care of country for each user and hide the products for those users which doesn't belong to USA.