MHADA transfer of property in the name of grandsons.

Hello! My (diseased) grandfather had bought a land from MHADA. But he died unfortunately. Then MHADA transferred the said property in my Grandmothers name after all the legal documentation. Now the said property stand in my Grandmother's name. My grandmother also died few years back. My mother was only child of my grandparents and she also died. As my mother was the only child now I and my brother become the legal heir of the said property. Now when I approached to MHADA they want us to get succession certificate from court for transfer of the said property in my and my brother's name jointly. I told them that now there is no other legal heir. (Grandparents died, only daughter died) So requested then to transfer the property in our name (me and my brother). Is the succession certificate mandatory provided the said property is to be transferred in our (Me and My brother) jointly. I have heard that getting a succession certificate is a big lengthy task. Is there any other way?