The Solis Export Power Manager second generation can monitor and control the exported power for identically sized Solis inverters.
Model EPM-1 is suitable for single phase and EPM-3 is suitable for three phase inverter. 2nd generation of the unit works with both phases. See the separate manual for 1ph installation.
Please note that the Solis export power manager can only control identically sized inveters (eg 3x 15kw). It is not possible to control smaller and larger inverters at the same time.