Assalamu alaikum muhtaram hazrat ji ,adaab,mera sawal ye hai k mery nana ne two shadiyan ki .first wife se aik daughter hai and doosri biwi se 5 children hain mery nana ne apni first wife ko house ka aik hissa likh ker de diya hai ,meri nani ne wo hissa apni daughter ko likh ker de diya hai. tu kiya iss main doosri biwi k children haqdar ho sakty hain k nahi .jazakallah.
بسم الله الرحمن الرحيم
If your maternal grandfather gifted a part of house to his first wife and gave it in her possession, she became the owner of the part and the children of the other wife will have no right in the same.
Allah knows Best!
Darul Uloom Deoband