[Zope] Deriving ZClasses from Other Product's ZClasses

[Ronald L. Chichester]

Can you derive a ZClass in one product from a base class in another
(separate) product?

Suppose, for example, that you have a "library" product, i.e., one that
is used to hold the base classes for a variety of other generic objects,
such as people, organizations, and documents.

Other products could use the "library" classes to derive new -specific-
classes, such as employees (from people), clients (from organization),
and templates (from documents).

This way, multiple products could share objects with a common base
class.  

Which begs the next question...

Can you search for multiple classes by searching for the base class. 
E.g., there is a (base) people class, from which other classes, such as
"contact," "employee," and others are based.  I know you can find all
the employee classes, and all the contact classes, but can you ask for
the "people" class and get all of the classes that are either a people
class or derived therefrom (e.g., employee, contact, etc.)?

Ron