Which film did M1 and M2 distribute and M3 and M4 distribute
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.film .
?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M1 .
?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M2 .
?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M3 .
?x0 ns:film.film.distributors/ns:film.film_film_distributor_relationship.distributor M4
}