Asunder = apart Quartet = a group of four dissension = strong disagreement; a contention or quarrel; discord. Rend asunder = tear apart I looked around and saw the most of the remaining women were now having fights with their husbands. Even Jordan's party (a group of four from East Egg) were torn apart because of disagreements / quarrels.

Even Jordan's group of four from East Egg, were split apart by disagreements and arguments. If you rend something asunder, you tear it apart.