Minecraft's got an "Open to LAN" feature, which can be used to set up a local server when two computers running Minecraft are on the same network. Some young relatives of mine use this to play together whenever they're in the same house, but they'd like to be able to play together from their respective residences.
A server is not optimal because it's a bit complex. I've tried using Tunngle to spoof that the computers are on the same connection to no avail.
How can I convince Minecraft's "Open to LAN" that their two separate computers are on the same network?