ESS mode to private 'grid'

Anyone know if it is possible/feasible to connect a second Quattro using ESS mode to a primary system which is creating a private grid? If it is possible, what 'grid' specification would I need to select? I am assuming that it would need to be 'Other'. If that is true, would I need to set up any other specific settings in the ESS assistant? The private grid is a Quattro 10000/48, venus GX, BYD B-Box 15Kwh and 6000watt solar PV AC connected and is my primary system. The secondary system is for an outbuilding and is a Quattro 5000/24, CCGX, 1000Ah agm batteries, 2000watt solar pv, ac connected. I would wish to install ESS mode on the secondary system. The two systems are approx 150m apart and I do have an existing 6mm SWA cable between the two systems.