Christians: Why is salvation not a GROUP matter?

Think about this, please. If Adam & Eve's sin caused all the descendants of the entire human species to be born in Original Sin, then why are judged after death as individuals? Why not have group or entire species Judgment. Thus, a man could only go to heaven if his entire family would also be eligible--or nation, subculture, corporation, business, university, or wherever he was a "group member"? , [ P.S. BTW, do you know the first reports of individual judgment came to Greece in the form of a "rumor of a new idea" given from the school of Socrates, described by Plato? Before that, ALLA humans went to the Underworld, regardless of their individual merits.]