Four young couples go for a stroll and come upon a river.
They find a boat, able to carry two persons at a time.
The girls, of course can row.
But there is a problem: the girls are extremely jealous.
So there is an agreement:
No girl may stay in the company of another's boy friend unless her own b/f is present as well.
How do they all get across? They can't.
But one of the boys spots a small island in the river,
which can be used for intermediate loading and unloading.
Now is it possible?