I can ping the PC the opened it game to LAN.
I can also start multiplayer, add a server like 'meepcraft.com' and play on that successfully.
I just can't seem to join my kids LAN game when they play together.
I'm not quite sure what this new HomeGroup versus WorkGroup settings are in win 8.1. I'm not even sure if it's that important as my modem/router is the one dishing out the addresses to devices...