Custom organisation schemas and ckanext-hierarchy

ckanext-hierarchy instantiates the view singleton for organisations, and so does scheming, so there can only be one. Is there a way to have both, apart from implementing hierarchy as part of scheming?

Start by examining how ckanext-hierarchy and scheming each instantiate the organisation view singleton. Determine whether both can coexist without folding hierarchy into scheming, then document or implement the agreed integration path and verify that organisation schemas and hierarchy work together.

Written by the indexing model from the issue text.