(Hindu)Property claim by stepmother in father's ancestral property

My Father(religion-Hindu), passed away 6 month back, he was 65 yrs old. My father had 2 children, me and my sister. My mother passed away when we were young. He married second time around 10-15 yrs back with a woman who already had 2 girl children from her first marriage. Now my stepmother wants to have a claim in my father's ancestral property. Question 1:-> Currently my grandmother has a house in her name, she is still living. If my grandmother transfer 1/4 of her house to my name, can my step mother claim a part of that house from me? Question 2:-> Can my stepmother claim maintenance from me? Currently she is already working and is working, and has her own house in her name already, from which is earning good rental income, and also she has two daughters, out of which one is married.