I would use Freddie's script for broadcasting to different computers:

<Label W1 Local SendWin "Warhammer: Age of Reckoning, Copyright 2001-2008 Electronic Arts, Inc.">
<Label W2 192.168.0.2 SendWin "Warhammer: Age of Reckoning, Copyright 2001-2008 Electronic Arts, Inc.">
<Label W3 192.168.0.3 SendWin "Warhammer: Age of Reckoning, Copyright 2001-2008 Electronic Arts, Inc.">

<BroadcastKey 1>
<SendLabel W1, W2, W3>

Replacing the IP addresses listed above with your ethernet IPs.