What is the ruling when a man tells his wives collectively, 'One of you is divorced,' intending a specific wife?

Primary text

When a man states to his wives, 'One of you is divorced' (Ihdakun talāq), intending one specific wife, only that intended wife is divorced, and the ruling reverts to his designation. He remains obligated to provide maintenance for all wives until he specifies the one divorced. If the divorce was irrevocable (bā’in), he is prevented from having marital relations with any of them until specification occurs. If he then specifies, 'I intended this one,' only she is divorced. If he states, 'I did not intend these three,' the fourth woman (if there were four) is divorced. If he retracts and states, 'I erred, I intended this one,' the other woman is divorced.