Approval Rules based on Position Hierarchy

Summary

How to build approvers list based on HCM Cloud's Position Hierarchy, not the Position Tree?

Content

All, 

I want to use Position Hierarchy to assemble approvers list for Approval Rules. When I looked into it I found that Approvals uses Position Trees. From Doc ID 2162878.1 it seems we cannot use HDL to load the position tree. We have hundreds of positions and we do not want to build the tree manually and synchronize the tree with our positions. In HCM Cloud we can use HDL to load Position Hierarchy object, but that's different from Position Tree. Is there a way Approval Rules can be built based on HCM Cloud's Position Hierarchy, not on Position Tree?