Clustering using voronoi volumes

Hello ,

I have been working on a problem where i have some 10000 particles inside a cylinder with their co-ordinates in r, theta and z . Now using the standard MATLAB commands i have found the VORONOI volumes (edges,facets etc) . Now I need to find the clusters of these particles inside their cylinder in order to study the dynamics of clusters of the particles on the whole . So how can I cluster these voronoi volumes ? Is there any code which I can refer to ? I was thinking that Voronoi volumes have just particle inside them , so how will I start clustering them ? (Is it based on the distance ? )