As per available data....... Being barter exchange ....
According to AS 18, the barter exchange is to be considered at FMV
You can open a bank account (say, Barter Bank) which gets nullified at the end of the exchange.
1. For sale of land A.
a. To land A Cr. Rs. 800,00,/- .... By Barter Bank Dr. Rs. 800,000/-
b. To land A Cr. Rs. 200,000/- By Short Term CG Dr. Rs. 200,000/-
2. For Purchase of Land B.
a. By Land B Dr. Rs. 600,000/- To Barter Bank Cr. Rs. 600,000/-
b. By Amount Receivable/ seller of land B Dr. Rs. 200,000/-
To Barter Bank Cr. Rs. 200,000/-