Breadboard has a variety of special features, one of which is it is on the lowest level with everything else above it. I did what started out as a part but ended up being a fzz (due to performance issues and Fritzing bugs) with subparts for an education board for someone that contains an internal breadboard. I doubt that you want or need breadboard for this, but may not be understanding what you are trying to do entirely. The moduleid field in the fpz is important (along with a variety of things in the tags) to get it working correctly. @steelgoose is the expert on this level of Fritzing (he is where I have learned most of what I know).
Peter