Kharijah bin Zaid bin Thabit (may Allah have mercy on him) says: It was said that if a group of people die together in a calamity (for example: a wall collapsing, drowning, burning) and the time of death of one is not known to be before the other, then none of them inherits from the other, nor does anyone else become deprived of inheritance because of them. Each one’s living heirs will inherit from him, as if there is no kinship among the deceased.
Hadith Referenceسنن سعید بن منصور / كتاب ولاية العصبة / 1418