Recently, Doug West, Excelisys, published an interesting and simplified technique to manage hierarchal portals in FileMaker.
Still, it relies on a data model that makes the handling of hierarchy difficult (move, duplicate, sort) or impossible (many-to-many relationships…)
Here is an alternative based on the very same example (and the same data), using FileMaker 12 ExecuterSQL function, in combination with FileMaker recursive capability. Custom Function