Clustering a pair of 3 points for a given x position?

#1
Hi all,

If i have a pair of points that have different y positions (A,B,C) but with the same x coordinate, is it possible to cluster this pair of 3 points together and not individually? I'd like to see the occurrence of this pair of 3 points together in a given sample and see what pair (A,B,C) is most frequent.
I've seen most of the clustering algorithm can cluster points for a given position (x,y) but not a pair of several points for a given x coordinate.

Any help would be much appreciated.

Thanks.