Teaching Slony replication to select slave nodes
I don't see a way to do this directly.  As I understand it, Slony sets replication destinations on the table, not row, level.

How I would solve this specific problem would be to materialize views based on replication destination group, and then use triggers to maintain those.  Slony should then be able to replicate these tables to the slaves.  I don't know if you can have triggers on the slaves that populate the main tables, but if not, there are ways around that. This requires decoupling the initial tables from the replication, and adds some complexity, of course.