You're right, In this case you'd need different segments for each side of the window. There will inevitably be some slicing operations that the script can't handle, especially for more complex styles, In which case I'd probably duplicate the window and slice the two versions using different settings to get all the segments that you need. That said, I wonder in this case if it might be better to create the frame and the sashes separately? That way you would also have the potential to open and close them if you like. To do this you'd probably need two additional generators, so you'd end up with one for each sash, and one for the frame.