Sister claim on Intestate Father property

We are three brothers and three sisters .all are married. my father has died intestate in 1997. my mother also died in 2009 .my father had three house properties (ancestral property but partition done between father and my uncle before death ) . we three brothers have mutated our joint name in properties in 2016. my father has died with some loan liabilities(unaccounted)what we brothers repaid in cash and we expended a lot of money over our mothers treatment and livelihood and look after. No sisters supported in our mother's illness (physically or financially ) ,look after and treatment. we are willing to sell one of our property for our financial requirements ,when we are in process of selling the property with consent of three brothers ,Our one married sister have risen a claim over properties and has served a legal notice for division of all properties now on december 2020. among all brothers and sisters.if we three sell the property without consent of sisters then :- is it a criminal offence ? is the registry would become in valid? what course of action you suggest us