There is a GSPathOperator method: - (BOOL) subtractPaths:(NSMutableArray *)SubstactPaths from:(NSMutableArray *)Paths error:(NSError *__autoreleasing*)error;
So, in Python you could do something like GSPathOperator.subtractPaths_from_error_( topPaths, bottomPaths, None ) where topPaths are collectively subtracted from bottomPaths. The resulting paths are stored in bottomPaths afterwards.
It is Python, and if you want to apply at export time, you will need to write a plugin. Do you have experience in Python? Then read the Plug-in tutorial, otherwise start with the four Scripting tutorials.
Hint 1: Write a plug-in, and apply it as a PreFilter parameter. That way, the components are still available to your code at export time. (Before decomposition.)
Hint 2: You can add a white attribute to a component with something like myComponent.userData["white"] = True, so you can query it with if myComponent.userData["white"]:
and then go on to decompose it and subtract it from the rest.