I would like to set up an EQ2 server where the only ones who
could play would be one on my LAN.
I currently have WoW/MaNGOS set up this way where 1 computer
works as the server and 3 others have the clients where the
3 clients have their hosts/realmlist pointing to the server.
Is/will this be possible with EQ2Emu ?
If this is possible how do I go about it ?

It is not possible now to run a private server as you describe it. However, you can set up a server with a Locked feature (in the loginserver.ini) and grant access only to those characters you wish to gain access (see variables and characters tables).
There may someday be an option to run private eq2emu servers, but at this point there is no reason. There is nothing to "play", so to speak. Your best bet, install a compatible client, hop on someone elses server to check things out.