Nomination Of My Family Members Where I Jointly Held Share-certificate

I am a joint-holder of share certificate of a flat in registered co-op hsg society in Mumbai with family (Wife and two children of my late younger brother). The flat was in my late father's name, and he made a Will giving equal share to me and my younger brother in the said flat. The Bombay High Court gave probate to us. But my brother died during the Court process and his family names were registered on Share certificate along with my name. My name appears first on the share certificate and their family names appear later in following sequence. Right now there are no nominations. 1. My name 2. My late brother's wife name 3. His son's name 4. His daughter's name I'm a senior citizen and I intend to nominate my family members viz. My wife, and My two children My question is:- 1. Whether I have right to nominate my family members when I and my late brother's family jointly hold the Share certificate. If I have not right to nominate then what is the alternative. How can I ensure that my wife and children get their rights in the property after my demise. 2. IF I have right then in a NOMINATION FORM (Under the bye-law No.32) the 2nd and 3rd column indicate the printed wordings:- "I, hold the Share Certificate No. _ " and I, also hold the flat No._ " - How to proceed with the "I" wording when the share-certificate is jointly held. thank you.