Did M1 employ M2 and M3 and employ a writer and star of M0
SELECT count(*) WHERE {
?x0 ns:film.actor.film/ns:film.performance.film M0 .
?x0 ns:film.writer.film M0 .
M1 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
M1 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
M1 ns:business.employer.employees/ns:business.employment_tenure.person M3
}