What company that M1 and M2 acquired and M3 and M4 were acquired by acquired M5 and M6
SELECT DISTINCT ?x0 WHERE {
?x0 a ns:business.employer .
?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.companies_acquired/ns:business.acquisition.company_acquired M3 .
?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M4 .
?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M5 .
?x0 ns:organization.organization.companies_acquired/ns:business.acquisition.company_acquired M6
}