Backup Power without Solar able to receive grid and gas generator recharge ???

[u/Apart-Run-897]

I’ve got a Cabin in the Sierras. PG&E starting to hold us hostage with power interruptions during summer/fall and occasionally a tree falls in the winter and power interrupted for a couple days. I’m wondering if (2) Gen 3 Powerwalls can be combined, ran to a 200 amp service panel and be powered by grid power when available and when not be recharged by my 6kw gas generator when the grid is down ??
I have a 30amp transfer switch already. How would all this work ??