by Jim » Fri Jul 08, 2011 1:01 pm
There is no such feature built into ShopSite. The only way to add multiple items to the cart at the same time is to use the Multi add to cart type template for pages and product shown in the online help.
http://www.shopsite.com/help/11.0/en-US/install/custom.template.multi-add.html
But that would not do any checking to see if the same item is in the cart more than once.