Joint family property

Good morning sir/mam my grand father has 5 children 1 women and 4 men,women after the elder men,my father is 4th son,my grandfather was earned 2 hoses where they lived, one on his name and another on his wife's(my grand mother)name,he registered as the my grand mothers property will share after her passes away among all his sons and daughter,my grand father was died in 2000 so the property remains same,and we all are living very far from properties and we dont know what happening there like so ,now recently i hear that my grand mothers property was sold by 3rd and 4th sons without giving any information to reaming(1 son and daughter,and my father)even we didn't sign any signatures,even we didn't call for it,can we have any chance to proceed any legal action?especially as grand son and grand daughter( i have a sister),does we have a chance to proceed legally?to claim our share? please inform me clearly and as possible cases all we are Hindu thank you sir/mam