Just a typical Japanese open ended story. Where you, the reader, can come up with whatever your little heart desires.
I, for one, think they all enter into a weird relationship of yuri desire. Each one liking the other, each one allowing the opposite to fulfill their love. A yuri circlejerk, if you will. Loving one while looking at the other. Quite possibly the oddest form of NTR to ever exist. But, one I can get behind.