[Zope] Several levels of message privacy/read access?

[XavierVergésFarreró]

I'm new to zope. I have browsed the zope book and
think that I like zope very much.

I'd like to have something similar to a blog, where
the different entries and comments can be hidden to
different sets of users. This is for my kid's school,
and here are some of the access possibilities that I
think that could be useful for a given entry:
-everyone can read it
-only the creator can read it.
-only teachers can read it.
-only parents and teachers can read it.
-only the kids and the teacher in a class can read it.

There is an additional level of complexity: if this
application proves to be useful, other schools in the
neighborhood may use it, so probably the school should
also play a role in the access rights. 

Any hints of what could my starting points be? There
are so many products that look nice that taking a
first step is hard!

Thanks in advance.

-Xavier

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