Is it possible, out of the box, to create promotion conditions that use order form addresses? I need to restrict a free shipping promotion to only the US. I've tried using customer segments to do the restriction, but it has some holes.

Customer segments do not appear to work for guest checkouts, which excludes them from the promotion. Also, the logic for addresses in the customer segment matches on only ANY or ALL addresses, which doesn’t really help with their current order form’s addresses. Customers could potentially have multiple addresses that may contain countries outside of the US, which would exclude them for the ALL match even though they may have chosen a US address or falsely include them when a non US country is selected as the shipping destination.

If not, can custom shipping promotions be created within code and still get the benefit of number redeemed and the ability to turn off?