Right now, we have the three alliances and three races in each, conveniently located next to each other.
In some cases, this works well enough - e.g. the aldmeri dominion (though the khajiit might be a slightly iffy point there). In other cases, this is completely unbelievable (argonians side-by-side with dunmer side-by-side with nords? OH PLEASE...)
So, my question is this - assuming that we need 3 sides - but let's forget a bit about superficially convenient geography, let's consider history, lore, favouritism, etc - How would you divide the 9 races into 3 alliances? (No need to have 3-3-3 division, mind. Mix and match as you want! Heck, make one or two races fighting alongside molag baal entirely if you want!)