Separate water tank in builder floor

We stay in building with 6 flats, 3 front 3 back, and we are on the top floor. 6 flats have 4 water tanks on roof. But being on top floor we were always facing water pressure problems. Thus, we installed a separate tank on our roof which is being filled simultaneously with other tanks. We actually disconnected our pipeline from the common tank and connected to the new separate tank on our roof. The other 4 out of 5 flats are pressing us to pay more than half of all expenses like electricity bill plus any repair job in motor or submersible pump which we are not agreeing to because our point is that the use of water is similar when we are using from common tank. Installing of separate tank was a forced decision as we hardly got water when taps were being used in ground floor or first floor. Now my question is can we approach the Lok Adalat directly without involving the district court?