Seven people A, B, D, I, N, R and S are sitting in a row facing the north.

R sits third to the left of S. I sits second to the right of D. D sits to the immediate left of R. A sits to the immediate right of B. A does not sit on any of the extreme ends.

Three of the following four are alike in a certain way based on the given arrangement and thus form a group. Which is the one that does not belong to that group?8543