Just a point of clarification on your original post - there’s no concept of hierarchy within channels themselves. You can manage access to sets of channels using roles, but there’s no subchannel concept.
Here’s the client documentation on setting up a filtered pull replication:
http://developer.couchbase.com/documentation/mobile/1.2/develop/guides/couchbase-lite/native-api/replication/index.html#filtered_pull