Four of the following five are alike in a certain way and hence form a group. Find the one that doesn’t belong to that group.

Study the following information carefully and answer the questions given below. Eight persons O, P, X, Z, K, M, G and H are sitting on a circular table such that four persons are facing inwards while four persons are facing outwards alternatively, but not necessarily in the same order. G sits third to the left of H whereas M sits second to the right of H. Two persons are sitting between M and K. The number of persons between K and G is same as the number of persons between H and O, when counted from the right of K and O. Z neither sits facing outside nor adjacent to M but adjacent to P.