[Zope] Best way to do "links"

[Oliver Bleutgen]

Hi,

I am unsure how to achieve the following in a product:

I have a folder with templates which shall be used to render articles. 
This folder will be the central repository of templates for all articles 
which find it in their acquisition path.
Now, I want be able to dynamically assign (and change) templates for a 
given article, and if I edit one template it should reflect in all 
articles which are configured to use that template.

In http://lists.zope.org/pipermail/zope-dev/2001-May/011187.html Shane 
Hathaway  describe hardlinks, which seem to do what I need.

i.e. I then just do
t = template_folder.one_template
self.template = t

I looked at how ZSQL-methods solve that problem (usage of 
SQLConnections), and as far as I can see ZSQL-methods just store the id 
of the ZSQL connection and use that everytime they need to access the DB.

Is that right and if so, why is it done that way?
Doesn't give that a performance hit?

And the last one:

Will the above described method still allow import/export these instances?

cheers,
oliver