Do you know how many groups there will be? If so, just get the x and y coordinates of each point using find(), then pass them into kmeans().
If you don't know then you could use some other clustering technique, like dbscan.
Or you could use pdist2() and cluster that by thresholding. It would be simple but it would probably require that the groups be well separated (unlike dbscan).
There are other unsupervised clustering methods that you can use. Take a deeper dive here: https://www.mathworks.com/help/stats/cluster-analysis.html
