Is there ways to make a atk factory only used for some instances

[Bolian Yin <bolian yin sun com>]

Hi Padraig,

I met the problem in gnome-canvas-item. Gail has impl for 
gnome-canvas-item, but programmers can add many functions to a 
gnome-canvas-item.

For example, a gnome-canvas-item support an action in some context, and 
want to add a action interface to the atkobject creates for it. In this 
case, I cannot register a new factory to create the atk object, or all 
the gnome-canvas-items will create their atk objects using the new factory.
Is there ways to make a atk factory only used for some instances of 
gnome-canvas-item, and in other case the default (gail) factory will be 
used?

Thanks,
Bolian