Onnevting 4x Growatt GBLI6532 6.5 kWh batteries

[Newbie1985]

I have 2 6.5 kWh GBLI6532 Growatt Batteries connected to my Growatt SPH6000 Inverter. I would like to add 2 more batteries. The datasheet shows you can connect 4 in parallel but no manufacturer instructions on how to achieve this. Can someone who has done this confirm whether it is possible and if so how they achieved it please.

Thanks you for your help