Was M2 produced by a film editor that M1 was edited and produced by
SELECT count(*) WHERE {
?x0 a ns:film.editor .
?x0 ns:film.editor.film M1 .
?x0 ns:film.producer.film|ns:film.production_company.films M1 .
M2 ns:film.film.produced_by|ns:film.film.production_companies ?x0
}