US shipping rates are pretty standard for us, so it's easy to let customers go through a complete and seamless order/payment process. But international shipping rates vary so greatly that we can't set up a standard rule to allow a full order process. We would have to check the shipping rate and give them a quote before allowing payment.

How is it possible to have ZC distinguish the two so international customers can get a shipping quote first before picking up their cart again and making payment?