46 kW solar battery based system with grid back-up

I am putting a solar system together for our hotel in Nicaragua, where electricity is expensive (21 cents/kW) and there is no feed-in tariff. As most of our energy consumption is at night (70%), the batteries are the core of the system. I have ordered a 144 kWh Ni-Fe battery bank and 170 Yingly 280W panels in China, and am now looking for at setup for inverters and solar chargers.
Our system here is 120/240 split phase, and our load is between 4 and 20 kW.
My idea is to order 6 Schneider XW+ 6848 inverters, 3 Power Distribution Panels and 9 XW+ 80-600 chargers to make 3 blocks of dual inverters in parallel.
The whole idea is to be as grid-independent as possible, charging the batteries each day and discharging them in the night, and only use the grid when the batteries are down to 20% SOC, probably in the late night or early morning hours.
My doubt is whether this will work without a transfer switch, as the information in the Schneider documentation is difficult to understand. They state that the risk with not using a transfer switch is that the last inverter to open will have to handle the overall load current, so if a higher current rating is needed than the internal pass-through capacity of 60 Amp (and I will need that) then it is necessary to use either an external contactor or a transfer switch. But then I understand that it will not be possible to configure a system with an external transfer for load-shaving (selfconsumption) - not sure why that is so.