[Zope] Override members values

[Garito]

Hi all!
I need to override the value of some members of my product

I think the correct way was __getattr__ function but I read some list's 
messages telling to use __getattr__ only if you don't have other way

How can I override only the value of some dynamic members?

I call dynamic members to the members that the user adds (with a 
property or an object)

Why?

Because I would like things like:

Object.member1 -> 1 (if you are a manager)
Object.member1 -> 2 (if you are a normal user)

or

Object.member1 -> 1 (for firefox users)
Object.member1 -> 2 (for ie users)

Where member1 is a property at property manager (for example)

Thank so much!

-- 
Mis Cosas
http://blogs.sistes.net/Garito