I know that I can use locked alliance(s) to set an initial state of war, but is it possible without using them...?

Failing that, is there any way of creating about 15 LAs (it seems the editor allows a max of 4)...?

Why don't you want to use locked alliances? Is it because you don't have C3C or do you want the civs to possibly be at peace later? Is it something else?

I'm pretty sure that's the only way to have a set up war.

What I am trying to do is this:

I've got a scenario with 14 playable civs, but I want to introduce some others which are a halfway house between standard barbarians and "normal" civs. This involves giving them a few settlers/units at start up and the ability to build a limited set of extra units (no settlers), so that they can act as an early obstacle to the "real" civs.

I want them to act as barbarians - so what I want to do is have these civs in some form of locked alliance with each other and locked at war with all the playable civs, but without having any alliances between the playable civs.

Is this possible...!?

Using locked alliances I am pretty sure that you can do that. It will also help to make the barb civs all have the highest level of agression and all be in the same cultural group. Civs in the same culture group are programed to like each other and dislike civs from otehr culture groups very slightly.