to do the work you are talking about you need a knowledge of local conditions,however there is a dept that deals with overseas positions, write to the govt affairs dept or get info from the nearest overseas consulate to the area you wish to work in for advice. Failing that of course many churches along with aid and red cross agencies also work in many of these places. I would write one letter just changing the heading for each and hit them al;l together that will save hanging around for weeks after each reply you'll get them all together.