What you want do looks weird, you can't use mod_cluster for that. you need to use mod_proxy_balancer.
configure the 2 balancers (cluster01 and cluster02) with the nodes corresponding to them.
Or use two instances of mod_cluster with different ports 6666 for the requests to cluster A and 6667 for the requests to cluster B ?
that means 2 instance of httpd running on different port. I don't think you want that
Oh well, so mod_proxy it is