I predict there will be another game in volume 8/9 similar to the one in volume 2, except with Ajisai joining in. The conditions will be:
if Mai wins, Renako has to marry her
if Satsuki wins, she gets to marry Renako
if Renako wins Mai & Satsuki have to marry each other
And if Ajisai wins Mai & Satsuki have to marry each other, but Renako will have to date all 3 of them