Add a switch. I don't know of a 10 port, but there are plenty of 16 port switches out there.
Everybody connects to a port on the switch.
Uplink port of switch goes to one port on the router which connects to internet.
Router has MAC filtering (allow) only for the authorized machines. (so a strange machine cannot be plugged in and used, as would be the case if MAC is filtering to deny).
All machines have DHCP enabled, obtain IP address automatically, same with DNS.