mmmmhhh. I know MatMatic - but it can't do things like that because it would have to make a transmap of a character. And if you use the settings I've shown here you can easily transform the two textures by simply setting the transmap to a higher or lower value...

I've made a "quick and dirty" - render:
http://www.renderotica.com/modules/My_eGallery/gallery/General/ARCH200610012257031.jpg
(don't know if that link works that way in this forum ;-)

A.