When I was a kid shooting 135 format, if I shot different scenes with significantly differing development requirements, I would leave four blank frames between the sections of film needing different development. I never left less than twelve frames in any section so (yes) I wasted some film... but I wanted some room for error and wanted the film to stay on the reels. Before development, I loaded the rolls of film back into the camera and advanced to the approximate areas of unexposed film and cut in the middle. The point is, it can be done.
But... I responded regarding the "sheet film only" posts regarding the "Zone System".