R help - Mar 2008 - How to assign identifiers to objects being clustered

I have a number of non-periodic signals , that have been detrended and denoised.
Each signal is made up of a variable number of cycles non necessarily
of the same length.
We can now fit a regression model to each cycle and then use the
returned coefficients,
together with some other data, to form clusters.

We would like to keep track of which signal each cycle came from in
the clusters layout.
It must be a trivial problem. However I cannot pass such identifier to
the routines that calculate
the similarity matrix as it would be used in the distance calculation process.

So I ran out of ideas about how to keep the clustering objects
(cycles) distinguishable all
along the clustering process (calculation of similarity matrix and
later clustering).
Is that doable at all ?

Thank you so much,

-- 
Maura E.M