Right of second wife's children on ancestral property

My father married to my mother and I am only child(male). My father lived in a far city for his job later on my father kept a second lady with him without my mother's notice. we lived in hometown and he use to come once or twice a month to hometown. later after many years, we got to know that he had a second wife there and she was having 4 male children with him. my mother didn't fight with my father for it but relatives argued a lot. after a few years he died. My father was a doctor, whichever he earned, all is on the name of second wife. his shop, flat and other property, all was bought in the name of second wife. But in hometown, with some law, they entered their name. Now ancestral property is divided as two shares to wife and one share to son. I and my mother got 3/9 of whole property and they were given 6/9. now have suited an application that how can they get part in ancestral property as she was an illegal wife 4 old persons of our family (paternal uncles) have witnessed in court that my father was married to my mother only in their presence and they don't know who is that second lady came in existence now. My father purchased a property on my name in home town can I have legal views regarding this ?