Airtel black and airtel postpaid family plan

Currently i am paying 1500 for airtel black, wifi + dth + 1 postpaid mobile.

I have 3 more prepaid jio sims for which i am Currently recharing 899 for 3 months plan.

I wanted to know how much difference would it make if we make all 4 into airtel postpaid and add under airtel family plan and cam it be clubbed with airtel black current setup?