In radiant. Sometimes it can be helpful to build small sections which can be cloned and reused. I think the current answer to that is regions. It is my understanding that if one imports multiple regions each is a separate fully copied group of brushes. Regardless of the benefits, the implication is that if there if a flaw is discovered in the region (later on), one must destroy each copy and reload the region at each instance.
It would be nice if each instance of a region behaved like a symbolic link, where a change to the original regions would propagate our to the copies.
Maybe this is already possible, if so, I've not figured it how to do it. Anyone know?