6 men and 6 women? that's almost the entire cast, if it was for the Corleone's only...

it could be very simple: the five heads+Moe Greene...

or Vito with his four sons+godson

Michael with everyone he had killed...

but I'll tray it anyway:

anyway... Sonny and Carlo, Michael and Fredo, Kay and Apollonia, Vito and Barzini, Sonny's twins from the GF2 deleted scenes (they were hot)

and the last two females... uhhmmm young Carmella and mama Andolini