2x multiples ii and 2x batteries working together

Modifications
1

Hello, I have an installation with a multiplus II 3000 with a 7 kWh battery and a Venus GX.
I am purchasing a 15 kWh battery.

I can buy an identical inverter, Multiplus 2 3000, and configure it to work in parallel with the existing inverter. In this case you wouldn’t be able to use the 7 kWh battery, Only the 15 kWh battery.

I was thinking if I’m going to buy a new inverter, why not keep the Múltiplus ii 3000 with the 7 kW battery and the múltiplus ii 5000 with the 15 kWh battery. Both managed by the Venus GX?
Or buy a multiple II 5000 gx, work independently of the initial system?The current system has an energy meter at the entrance to the house, connected to the Venus gx.

2

Are the batterys the same cell count? Same bms? Same specs? If so you can connect them together on one system

If the multiplus 2 units are too far apart on prodcution date, parallel them canbe a challenge or not possible at all

2 separate systems on 1 GX is not directly posibble, but there are workarounds that can be done

3

The batteries are different, brands and models. One is from 2020, the other is current. Therefore the batteries will be different. Regarding the inverter, the multiplus II is from 2020, it is a multiplus II 3000/48.
I want to add a new inverter, another multiplus ii 3000, and try to make them work in parallel, to have more charging and discharging power.

Or buy a multiplys II 5000 now.
The Venus GX cannot manage both at the same time, for example by placing one MP 5000 with 15 kWh battery in the house’s air conditioning circuit, with and another MP 3000 with 7 kWh battery for the rest of the house?