[Therion] Color for one scrap in a Project

Is it possible to define color-map fg only for one scrap in a Project of about 50 scraps in several surveys? I have an "all-thconfig" file for this Project and there I have defined a light yellow for the cave. And in the scrap which I want to have in very light grey I have defined this very light grey, but it will overwritten. Many thanks for Ideas. Markus