Ruling on a man marrying his father’s wife’s sister or her daughter

The presenter: This is a letter we received from the sender Saud 'Abd Allah, address: al-Khafji, the Arab Oil Company. He says: Peace be upon you, and Allah’s mercy and blessings. And after that: I ask my brother, the presenter of the program, to present this question to His Eminence Shaykh 'Abd al-'Aziz ibn Baz. The answer is of utmost importance; I hope you will be quick to respond to it. He says in his question: My father has a wife, and he has children from her.
The Shaykh: If...
The presenter: My father has a wife, and he has children from her, and this wife has a sister. Is it permissible for me to marry my father’s wife’s sister, knowing that my brothers from my father’s wife call her “Aunt” (Khalah), and of course, she is forbidden to them because she is their maternal aunt, the sister of their mother? Is she forbidden to me because I am their brother? And does her status with regard to me equate to the status of the original maternal aunt, or not?
Answer: No, not with regard to you. The questioner, no, she is not your maternal aunt. You, the questioner, may marry this woman who is the maternal aunt of your brothers from your mother; there is no harm in it. You are a stranger to her, and she is a stranger to you, so you may marry her even if she is the maternal aunt of your brothers from your mother. In fact, you may marry the sister of your brothers from your mother. If your father’s wife has a daughter from a previous husband, then you may marry her, but your brothers may not marry her because she is their sister. As for you, you are a stranger, so you may marry the daughter of your father’s wife, and you may marry her sister because you are a stranger to her. As for your brothers, they may not; the daughter of their mother is their sister, even if she is from a different father, and her sister is their maternal aunt, so they may not marry her, and it is not permissible for them to do so. But you are a stranger to the daughter and to the sister. Your father’s wife is forbidden to you because she is your father’s wife. As for her daughter from a husband other than your father, you may marry her if there is no breastfeeding relationship between you and her. Likewise, you may marry one of her sisters because you are a stranger to her, provided there is no breastfeeding relationship between you two. As for your brothers, they may not, because she is their maternal aunt. And Allah, Glorified and Exalted is He, knows best.
The presenter: Thank you, Your Eminence, the Shaykh!