Hi there!
Sry for a late response to this topic.
I have seen you got recommendation to try DBSCAN as an aternative in this forum topic: Clustering with restrictions - wondering did it work or you managed to find another way for your problem?
If you use Hierarchical Clustering Assigner inside a loop and in each iteration change number of clusters and calculate number of different values for att2 per cluster you could get something but got a feeling this is not the best approach…
Br,
Ivan