I have a set of objects ready for clustering, say {O1,O2,....,On} Each such object carries an identifier/label/tag, say {a1,a2, ..... an}. My goal is to recognize the objects after clustering. That is I'd like to know which cluster object Oi has been assigned to and which are the other objects {Oj,..,Ok} in the same cluster. Unluckily I canNOT pass the identifiers to the function calculating the similarity matrix as they cannot be used as a similarity parameters. Likely I cannot feed such information to the clustering routines. My questions are: Can I keep track of which is which when clustering ? If the answer is "yes" then how can I accomplish that ? Thank you so much -- Maura E.M