Money on sale of house property.. urgent!!!

I have an ancestral joint property (4 owners) and all of us are planning to sell the house... My 2 brothers and I have 12.5% each of total share=37.5%.. And my elder brother has 62.5% share....

Now if we sell the property for say 1 crore.. I get 12.5lakhs.... Now if the buyer decides to show a total value of say 30 lakhs to save stamp duty...

So according to papers i get12.5x30% = 3.75 as shown in sale deed... So how do i keep the remaining 8.75 lakhs in bank.... In my account... Thanx in adv