Default order type bases on ship to address

Hi

We have defined Order type as Bill to Site and Ship to Site

Example Customer X Bill to site the default order type is as "Domestic order- Product " and this has 08 ship to site one of the ship to site we have default order type as "Export order-Product"

when sales order is entered the order type populated "Domestic Order- Product which is based on bill to Site, Where as Ship to site the default order type is Export- order - Product, we need that when sales order is entered, the order type default value to be populate from ship to site , rather then Bill to SIte