Whichever machine you decide is to host, go to the preferences menu and to the network tab. Select the LAN option rather than the 28.8k-56k
Once that machine has started a network game (preferably as a dedicated server), all the other machines have to do is find LAN games under the multiplayer menu.
That's assuming they've got the right protocols (IPX/SPX protocol & NETBIOS, TCP/IP...)
That should get it working right
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