Were M4 and M5 employed by a company founded by M1 and founded by M2 and M3
SELECT count(*) WHERE {
?x0 a ns:business.employer .
?x0 ns:organization.organization.founders M1 .
?x0 ns:organization.organization.founders M2 .
?x0 ns:organization.organization.founders M3 .
M4 ns:people.person.employment_history/ns:business.employment_tenure.company ?x0 .
M5 ns:people.person.employment_history/ns:business.employment_tenure.company ?x0
}