Were M2 and M5 written by a person that M1 employed and written by M3 and M4
SELECT count(*) WHERE {
?x0 a ns:people.person .
?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
M2 ns:film.film.written_by ?x0 .
M2 ns:film.film.written_by M3 .
M2 ns:film.film.written_by M4 .
M5 ns:film.film.written_by ?x0 .
M5 ns:film.film.written_by M3 .
M5 ns:film.film.written_by M4
}