1. On he death of your grand mother her property get equally inherited by her 4 daughters or their children.
2. In that cases all the three aunt of yours or their children have equal undivided share in the property along with your mother.
3. So if you wish to become the sole owner of this property you need to purchase individual share form each of the co sharers.
4. Unless each and every co sharers transfers his share in your name you can not become the exclusive owner or sole share holder of this property.
5. You can get a gift deed done to make you the full owner of the property. The gift deed attracts least amount of stamp duty.