Yes, the system has public grid access. I run 2 independend ESS and have a free connection between the houses / ESS. Thats why I started thinking about the direction of using this cable. Of coarse, best is always automatic bidirectional use.
Grid might fail any time. Then both ESS go on working like intended. Unfortunately, load power and battery SOC might be in a unexpected state at grid failure moment. Thats why I like to have the 2 ESS in cooperative behaviour sharing batteries and loads inside a true microgrid. Its exactly the situation to run a island with several houses without public grid.
If this is working with master and one slave, it will work with any number of n slaves as long as the unbalanced power does not exceed the masters capacity. Therefore any operator with supervisor access needs to take care. It seems a feasable and lazy job, as battery SOC are changing only slowly.
The only unknown question seems for the moment: Is the master ESS able to consume power from its OUT1 to charge its battery. I am going to open another thread for this question to avoid specialists have to read too much stuff.