is there a function like “RoutingRule” for a transport connection via robot, human, vehicle controller?
Unfortunately not really.
You can get limited control over routing by using “To transport node” mode in TransportOut statement.
It might also be possible to use Python scripting to rewrite Transport solutions of product instances as they pass through transport nodes. This way you could do arbitrary routing through the transport system as long as the products eventually reach their original destinations.
I haven’t actually tried this so there could be blocking technical issues.