Which production company was acquired by M1 and M2 , acquired by M3 and M4 , and acquired by M5 and M6
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:film.production_company .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M1 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M2 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M3 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M4 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M5 .
?x0 ns:organization.organization.acquired_by/ns:business.acquisition.acquiring_company M6
}