Are the sons of her first husband mahrams to her and her daughters from her second husband?

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Check below answers in case you are looking for other related questions:
She breastfed a child thinking that it was her son; is the mahram relationship through breastfeeding established?
Is the husband of her husband's daughter a mahram for her?

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Related Answers:
Should he marry his paternal uncle’s illegitimate daughter?
Being married to a woman and her father’s ex-wife at the same time
The sister of the wife’s grandfather and the sister of her grandmother are mahrams to the husband just as her paternal aunt and maternal aunt are mahrams to him
She breastfed a child thinking that it was her son; is the mahram relationship through breastfeeding established?
Is the husband of her husband's daughter a mahram for her?

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