What was produced by a film editor employed by M1 and M2 and employed by M3 and M4
SELECT DISTINCT ?x0 WHERE {
?x0 ns:film.film.produced_by|ns:film.film.production_companies ?x1 .
?x1 a ns:film.editor .
?x1 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
?x1 ns:people.person.employment_history/ns:business.employment_tenure.company M2 .
?x1 ns:people.person.employment_history/ns:business.employment_tenure.company M3 .
?x1 ns:people.person.employment_history/ns:business.employment_tenure.company M4
}