I think it can indeed be used in the way you wish. To group zones that belong to the same surface you can use the <surface> element (or if a group of different surfaces the <surfaceGrp> element). Would that work in this case?
If there are not enough examples using it in the way you want, do feel free to submit additional examples at https://github.com/TEIC/TEI/issues since expanding the examples in the Guidelines is almost always a good thing.
Dr James Cummings, [log in to unmask]
School of English Literature, Language, and Linguistics, Newcastle University