Thank you!
Edit: Actually, dom3_data didn't work but DOM3_DATA works fine.
So, if you set things up in separate directories, you can run either like this,
Code:
DOM3_DATA=/usr/local/games/dominions308/ /usr/local/games/dominions308/dom3
DOM3_DATA=/usr/local/games/dominions306/ /usr/local/games/dominions306/dom3
And use whatever command line switches you normally specify.