[Zope] External methods writting "up" object hierarchy

I am trying to write an External method that evaluates a multiple- choice exam, and then writes the results into a directory object for the student within the Zope database. I cannot seem to figure out how to access objects that are Parents of the object from which the External method is called. Is this possible? And can this be done on another "branch" of the object heirarchy? For example, if A, and B are subobjects of X, can an External method called in A access B and its sub-objects - and how? (say, manage_changeProperties()). Thanks, JP Montse Rue JP Glutting jpglutting@mx3.redestb.es