It’s generally not recommended to use different batteries on a parallel installation.
Both inverters MUST share a common negative. With different batteries of different capacities, the first inverter to hit ‘low battery’ will shut down the entire system.
If the batteries share a common voltage profile, then there is no reason not to parallel the DC.
Both inverters must also be the same model & firmware, meaning that you cannot (currently) parallel a 48V and a 24V system.