[Zope] - OO paradigm

[Michael Bernstein]

I've been examining Zope with quite a bit of interest for a while now,
and I have a question about the basic architecture:

The object hierarchy seems to be 'exact', that is, strictly exclusive.
No object can appear in more than one branch of the tree. However, In
many cases, user oriented design requires several alternative navigation
hierarchies, which would require objects to inherit from more than one
branch.

An example would be an event calendar, where events can be organized
chronologicaly ( Years>Months>Days) but also according to an event
category heirarchy (All events>entertainment>music>concerts). These
heirarchies only intersect at the leaf node of an individual event.

Most product catalogs can be profitably organized using multiple
heirarchies as well.

So how would you do this in Zope? you could of course represent the
alternative heirarchies by branching off the bottom of the primary, or
as folder properties, but that doesn't seem as elegant or maintainable.
perhaps the answer is some sort of 'pseudo heirarchy' object that could
be placed at or near the top of the object tree.

What do you all think?

Michael Bernstein.