Removal of son's name as co-owner of property

I own two properties in Delhi, which are occupied by my two sons. Each property is under mine, my wife's and the respective son's name. I wish to revoke their ownership rights from both the properties. In all circumstances, they will not concede to my wishes. What is the legal way for me to go forward? I also wish to list these properties in my Will to my two grandson's after they reach the age of 21, and wish to give no rights except being a guardian to my sons. Please guide me. I have no will in place currently, my age is 75 and wife's age is 70.