Allow subdivisions on carrier selection
In some countries the cost of shipping products depends on the subdivision. For example in Spain sending goods to the Islands (which are a specific subidivions) is more expensive than sending to other places.
In this case it makes sense to use diferent carriers for each subdivision so the amount invoiced to the customer may be diferent depending on the destination.
So I propose to add the subvisions as pattern on the agent selection. As the subdivision is a tree structure I think we should follow the same behaviour as product categories and make test all the parent subdivisions of the party address.