If this is already somehow easily done, then please let me know and forgive me for the post. But so far I do not see this functionality or cannot find a guide that documents how to do this.
I am exploring multi-material printing right now and one feature that would really make S3D stand out I think would be the ability to select the different processes that make up a model - then create another process to handle the support layers. This would include brim, raft and support structures. This would allow people to more easily handle soluble supports in mixer style filament extrusion systems. Specifically I am wanting something like this that can easily work with the Chroma software and Mosaic Palette+ as it assigns color and filament type by process. Being able to easily break out one process and know that it would be used only for support type filament would be a major advantage for S3D.