Did M2 employ a sibling of M1 and employ M0 's editor
SELECT count(*) WHERE {
?x0 ns:film.editor.film M0 .
?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 M1 .
FILTER ( ?x1 != M1 ) .
M2 ns:business.employer.employees/ns:business.employment_tenure.person ?x0 .
M2 ns:business.employer.employees/ns:business.employment_tenure.person ?x1
}