LeaseHold Property Settlement

My Uncle (father's brother),single, unmarried, without any children, had acquired a lease hold property in New Delhi, half through pakistan partition claims while the other half through full payment in cash. On his death, he left a registered will in favour of my three brothers equally (1/3rd share each), which was substituted in their name around 45 years ago. One of my above said brother's, expired and his 1/3rd share was substituted in my mother's name 35 years ago. My demised brother was single, unmarried and without any children. My mother left a registered will of her 1/3rd share in my favour and she expired 15 years ago. This was her last will and no other will was made ever again. My mother and father have 7 legal heirs including myself. The rest 6 are willing to provide me with an NOC for the mutation of the Will. They are also ready to provide the Release Deed for the transfer to take place. In the current situation, 1) What would be the best possible approach for me to get the above said 1/3rd portion of the property transferred in my name that is how can i become legal owner of the 1/3rd portion of the property. 2) Also, can one of the current owners of this lease hold property sell/ transfer / gift his share to the other living owner and myself in equal share. Again, the current co-owner in question is unmarried, single and without any children. If so, what would be the best possible process to achieve the same.