I'm not technical enough to advise on that, unfortunately. They were super supportive and helpful over the phone and in person.
I'd recommend you reach out to them and ask what is possible.
I have a variation of the large system in my house, 2 batteries and 2 of the 5kw Growatt Inverters. It's incredible. I've had it for 4 months or so. I had it installed in my scullery as I have a converted garage.
I don't know when loadshedding is happening. The batteries lasted around 15 hours...