For the school, we can remap it as two separate polygons, as we did for the one here: https://www.openstreetmap.org/changeset/87596976

For the music school, we can do this too, though it will probably trigger some "amenity inside amenity" flags in Osmose (https://wiki.openstreetmap.org/wiki/Talk:WikiProject_Belgium/Conventions/Schools#Schools_operating_on_the_same_grounds_on_different_times_of_the_day)