I copied the Zeroshell folder twice as Zeroshell1 and Zeroshell2 … tried to run them both at the same time as different machines but only one of them works. The other one doesn’t work even though both machines have different IPs under the same subnet. 10.1.1.253 and 10.1.1.254 under 10.1.1.x subnet.
I needed two machines because the DHCP server has no option for more than one Gateways and DNS servers.
I suggest (if possible) changing the pop-up window for adding of Static IP Entries at the DHCP server with adding Range, DG and DNS for every client separately, not only IP and MAC.