Using hierarchies in the Application Engine object model OlapApi
The class 
    OlapHierarchies that serves as a
      collection of OlapHierarchy is part of the Application Engine object model  OlapApi. Every dimension keeps a list of OlapHierarchy and each of them caches OlapElements
      that belong to a particular hierarchy. As a consequence, every OlapElement has a reference to the OlapHierarchy
      that it belongs to.This implies that searching for parent or child elements of element E is performed on the hierarchy that is referenced by E.
Every OlapElement that is returned by
      calling the function OLAPGetElementList contains its owner
      hierarchy:
OlapElementList OLAPGetElementList(OlapConnection connection, string dimension, string hierarchy, bool onlyBaseElements, bool cache, bool throwException)
    Therefore, the list of parent elements of such an element that is returned by
      calling the function OLAPGetParentElementList can be
      retrieved from the hierarchy of the element:
public OlapElementList OLAPGetParentElementList(OlapConnection connection, OlapElement element)
    If an element is retrieved by calling the function OLAPGetElementList
      without hierarchy parameter, then the element references the default hierarchy and the parent
      elements are also searched in the default hierarchy.