Is it a sin from a religious perspective for siblings, their spouses, and their children to gather in one house without dividing the inheritance?

If the wife of each of you is not a mahram to the other, then it is not permissible for you all to sit together in one place without a barrier between men and women. This is because sitting together necessitates looking [at each other], makes it difficult to maintain modesty, and may lead to the breaking down of barriers and a relaxed atmosphere. This is not permissible between non-mahrams. Mixing leads to great corruption and harm, and the claim of pure intentions and good faith does not justify impermissible mixing. Allah Almighty commanded asking women from behind a veil, as it is purer for the hearts.