question: Which child of M1 's sibling was a film producer 's founder
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 ns:organization.organization_founder.organizations_founded ?x1 .
  ?x0 ns:people.person.parents|ns:fictional_universe.fictional_character.parents|ns:organization.organization.parent/ns:organization.organization_relationship.parent ?x2 .
  ?x1 a ns:film.producer .
  ?x2 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 M1 .
  FILTER ( ?x2 != M1 )
  }