question: What production company was founded by a person 's sibling , employed M1 , M2 , and M3 , and employed M4
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:film.production_company .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M1 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M2 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M3 .
  ?x0 ns:business.employer.employees/ns:business.employment_tenure.person M4 .
  ?x0 ns:organization.organization.founders ?x1 .
  ?x1 ns:people.person.sibling_s/ns:people.sibling_relationship.sibling|ns:fictional_universe.fictional_character.siblings/ns:fictional_universe.sibling_relationship_of_fictional_characters.siblings ?x2 .
  ?x2 a ns:people.person .
  FILTER ( ?x1 != ?x2 )
  }