rights of grand son in property of grand father

Hi, My name is kumar. i belongs to tamil christian , living in Tamil. my age is 41. my grand father (passed away) had a land of half acre in his native place, which consist of a house and vacant land and agricultural land. at present no body is maintaining this property. after the grandfather, my father and his three brothers collectively having the rights (to maintain) the estate. As of now our father also aged , discussed and agreed themselves (with his brothers) to separate our grand fathers estate within them as by some agreed terms and conditions. at present there are 5 grandsons (including me) are major (18+). but our father and his brothers didn't asked for any written consent with me (and other grandsons) in connection to the estate separation. is this legally correct. can they make a registration in registrar office without the consent of the grandsons. i think our grand father earned and purchased the estate from his own earnings. also he did'nt offered or created any legal document on the estate, infavour of his sons (ie our father and his brother) In this situation what is my right in my grandfather's estate.? please clarify thanks...