Uncle's Property

In 1978 my father's younger brother left home and none of us are aware about his whereabouts till now. Before leaving he had written letters to my father (who also passed away in 2015) and another uncle as to how his share of family property (close to 60 cents) should be equally shared between both of them. Both my father and the other uncle have been taking benefits from the property in the form of selling timber trees and agricultural produce like banana and pepper. Both of them have not transferred the property into their name. Currently my father's four sisters are also asking for a share of the property (in the form of cash, preferably) saying that they also have a right to the same. For this the property would need to be sold because none of us are in a position to shell out so much money. We are agreeable to the same. How could this issue be resolved in an amicable manner and what would be the process which needs to be followed in such a situation? Looking forward to your response