Thanks, Scott.

Although this was a very helpful and clear answer, FrameMaker is less so, apparently. I was hoping for something more along the line of other DITA authoring environments, where you can blend in and blend out elements belonging to specific domains. On the fly, and if you need them for another topic in the same project, you just blend them in again. Oh well, you can't have it all, they say ;-)

Ciao from Amsterdam

Jang