How to disconnect Fronius Devices

Have a new and additional Ekrano connected to my internal subnet to try out beta versions and ARM compiles. Although Venus Sunspec is disabled, all Fronius inside the same subnet are autodetect and appear in device list and Venus GUI. They are not connected to the same ESS / AC grid and I wont have them in device list. Is there another way to ban this devices than moving them into a own VLAN?