In the case of two divorced individuals with children of the opposite sex

How do they Islamically manage the children who are not mahram?

So essentially, if you have this Brady Bunch situation where a man has children from a previous marriage, a woman has children from a previous marriage, and they get married.

Can they get married? Because the children are not mahram for each other. Meaning that the children can marry each other.

When a man marries a woman, he may not then marry her mother or her daughters after that. They become haram for him. But his sons do not automatically become mahram for her daughters and vice versa.

So how is this dealt with?

If the children are young enough, meaning if they're still infants below the age of two, then you could breastfeed them and give them breast milk to drink. Five filling drinks that would then make that child a mahram to the new parent.

However, that's generally not the case. People are generally marrying and they have kids that are six, seven, eight years old. One thing that you need to realize, is that it is not impermissible for you to marry. It is permissible for you to marry, but you need to teach your children the concepts of mahramiya.

Yes, they can respect each other as brothers and sisters, but when they get to the age of puberty, then they will have to not come into physical contact with each other, they will have to cover in front of each other, and they will have to, display a certain level of decorum with each other, and it's important to do that because you do not want to blur the lines between what is halal and what is haram. But it is permissible and you could easily do it by making sure that at a certain age boys are in one room, girls on the other, so on and so forth, but it is permissible.

But you just have to be open and honest and straightforward. Educate the children about what needs to happen.