POW 25

So there were three of us men who each had a sister, and we all had to get across a river. But each of us lusted after one of the other's sisters. On coming to the river all we found was a little ferry boat that could only carry two people at a time. Say if you can how we crossed the river so that none of our sisters was dishonored by being alone in a boat with a man who was not her brother.