Demigod lan problems

Hi me and my friends lan demigod over hamachi because well basicly its what we do

but i have encountered an error when someone else on my local network wants to join the game (they are also on hamchi) they cannot connect to the other players.

The weird thing is that this is only true for a wired connection and does not happen when useing a wireless connection

e.g 1. my computer and brothers computer both wired to router cannot lan over hamchi

e.g 2 my computer wired to router my brothers computer wirlessly to router can lan over hamchi

any thoguhts on what could be happening?