I am guessing the reason is that as its an old dos game that does multi-player using IPX, they don't want to support people needing assistance setting it up.

I have not tried it but I would expect the instruction here http://www.dedoimedo.com/games/reviving/dosbox_multiplayer.html
should work just as well with this games as they do with the dos version of doom.

Thanks for the reply and link, will check it out.

I just thought GOG was trying to get Galaxy old and new games' multiplayer working to compete with Steam. There are several older games which work with 3rd party systems like Heretic, Hexen and Doom I & II.

Well I hope that's what Galaxy will be doing. ;)