What did a sibling of M2 found and a person that M1 was played by found
SELECT DISTINCT ?x0 WHERE {
?x0 ns:organization.organization.founders ?x1 .
?x0 ns:organization.organization.founders ?x2 .
?x1 a ns:people.person .
?x1 ns:film.actor.film/ns:film.performance.character M1 .
?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 M2 .
FILTER ( ?x2 != M2 )
}