It is very very easy because....................there is no residencies really, and if you come back to the US from any of these residencies you do dig up then you have to do them all over again.................. Of course you knew that right?
You might wanna check out the UWI (University of the West Indies) websites, there're three of them (Barbados, Jamaica and Trinidad) I think. You should be able to find information on residency training.
Unfortunately, there isn't a lotta online information on residency training in the caribbean but it does exist.