Another (but limited) way to do this is to make a cluster of your clusters, with each "sub-cluster" having a unique name. When you go to process this "Super-cluster", use "Cluster to array" to turn it into an Array of Clusters (which strips off the labels from the elements), process the (now) Array elements, and it you want to display it back as a Cluster, do an Array-to-Cluster (you might have to TypeCast the resulting Cluster to your saved TypeDef -- you did make a TypeDef of your Super-Cluster, didn't you? -- in order to get the Labels back, I'm not sure).
Bob Schor