Grounding two inverters (same ground)?

[Wolfonaship]

Aloha,
I have one 24v growatt supplying ac to a square d sub panel.
No grid tie
N-g bond in sub panel (not growatt)
Ground runs from sub panel to
House's main ground - I believe #4 wire into concrete slab foundation for 25ft+ clamped to rebar (passed inspection before pour.)
I have a seperate 12v system w/ inverter for small 110ac loads and mainly my dc water pump. It will have its own sub panel as well.
1) Can i ground both seperate inverters/ ac sub panels to the same ground?
2) If so can I run one sub panel box's ground to the other (shorter run than the connection at the #4 bare pigtail to slab)
3) Does each seperate sub panel fed by the seprate inverters still need their own n-g bond if sharing the same ground?
Thank you all very much!

 

[timselectric]

Should go directly to the house main ground.
Yes, N/G bond in Second panel.
It's a separately derived system.

 

[Wolfonaship]

Thank you very much!