Pbuffer and z-buffer

I wanna draw to pbuffer color buffer, but using the original z-buffer…for example i wanna draw a scene and draw a kind of object that shines…then i would draw it to the pbuffer but using the default z-buffer, blur and render it to screen…is it possible?

Another question: how do i share resources (textures , vbo and display lists) between current GL context and pbuffer?

If you are under windows,then you can use wglShareLists to share your textures,VBOs,ect. between contexts.