In theory, you could have a relay for each of the 8 Ethernet wires, and programmatically control that. But... you could also set up an OpenWRT router and if yo

In theory, you could have a relay for each of the 8 Ethernet wires, and programmatically control that. But... you could also set up an OpenWRT router and if you can't configure IPs in non-conflicting way, you could turn particular network interfaces on and off as it's basically a Linux box. Note that most consumer routers compatible with OpenWRT usually have only two network interfaces, even if they have multiple ports for one of them.