Hmm, a row might work out on that map, but I think everyone would have to start on the main island for it to work, so you would start very close to the other team. Then again, this is not necessarily a bad thing.
If nation waters are used (one per team I gather?), it may be easier to set up manual placement: the land player on the mainland, the water player in the sea, and half the land/sea away from the other team.