Property dispute between siblings and their son/daughter

(Hindu)My grand father died, as per my knowledge every present property is under his name. Grand mother is alive(everything is handled by her from past 24 years). My father and 3siblings(2son,1daughter-married), my father's elder sister and 2siblings(1son,1daughter-marrief), my father's younger sister and 3 siblings(1son-married,2daughter-married). Who all have authority on the property and how much? my father younger sister was married before 1983 and elder sister after 1983. Lot of income is coming through rent but my grand mother is only receiving it ,we are not able to take anything.