Can a reference process pull from a parent-level BP to a subordinate-level BP? The picker doesn't sh

We have a shell hierarchy with the upper level "A" and a subordinate "B" level. A Base Commit is created at "A" level. Through the "B" level change commit BP we'd like to reference the "A" level Base Commit. Is this possible? Are permissions and/or configurations different to account for the hierarchy?

The Picker used in the ("B" level) reference process is empty (appears, but returns no results), although there are Base Commits available, complete with SOV's.

We've used the same user (administrator) for everything setup/create/workflow.

We've created new project hierarchies with no other BP's aside from the two Base and Change commit.