[R] How to recognize objects in clusters

[Maura E Monville]

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