[Zope-dev] How to know the execution context in a product

Hi I try to know the context of the execution of my product to overrite the values of the properties of my product It will be like a sof-link I have the property Master. These property is an url to the real object When I execute the ZMI I would like to see the real content of my object but when I consult a property in a ZPT or a DTML or another context I would like to retrieve the property in the context of the Master object How to make these? Thank you