What film producer employed M1 and M2 and employed a film producer
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.producer .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person ?x1 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
?x1 a ns:film.producer
}