I had a similar problem when I lived in SE Asia. I found, as has been suggested, hotel stays and car rentals to be the easiest way. The problem with that is that you can only do one account at a time, and you're obviously looking for a way to keep all 4 accounts active. Probably the most effective way is going to be to fly.

edit: or the Tropicana code from someone, as Hugh Jorgan just suggested.