Two buyer Two NRI Seller; How many challans

We are planning to purchase a property jointly owned by two NRI. We are two Indians.
I understand, that we have to get TAN and deposit the TDS and then fill-up form 27Q. Say the total TDS is 20L. Total four 27Q form is to be filled up.
Our problem is that
1. should we pay TDS in four parts of 5L or
2. it would be sufficient if we pay 10L each without dividing, and then that can be divided while filling up form 27Q?
The person filling up for us is also confused.