Yes, but then i have to finish off the winner.

I didn't read through all the posts but I got the general iea of what's being asked. I don't know if this has been answered yet but I noticed throughout my games that the AI will ALWAYS try to have a ceasefire with any player doing better than itself. I know this because in a game that had four players left, I had one ally and I had just declared war on a second ally. This latter AI kept asking me for a ceasfire (even though I had 0% "likeness" with it) until the fourth faction was destroyed, at which point it suddenly went berserk on me. Of course this means that if you're not careful, and don't play with allies, you may end up ganged up on all fronts from all AIs (this happened to me a lot during my beginning hours of experience on hard). Just my two cents

Like the OP, I just did a vs. 3 Hard AI's.

I wanted to get the vs. 1+2+3 Hard AI's award thingy. I usually quit when the game is decided.

The first AI I met I aggressively pursued an alliance with. I set up a border, fulfilled the requests quickly so I would get a new one faster, etc.

And I did get a trade alliance, cease fire, eventually peace.

The demands later are at times impractical - destroy X installations from the player furthest from me that I'm not currently fighting, e.g.

I would like that the missions was slightly more generic - 'Hurt' that player, and you can destroy any of both ships, civilian and military installations. Frigates counting 1/2 or something, for instance.

The game finished with us still allies, and it had been rather useful, I thought.

I also didn't get the accomplishment since a requirement was to do it alone. (I thought that applied to having a teammate pre-setup, or two humans vs. .. *sigh*.).

I got the 3 Hard AI achievement by doing a 2 hard vs me and a hard. Just before we finished the 2nd enemy, I turned and stabbed my ally in the back, and I got the achievement. I was surprised.

not if he's ur ally and ur the only ones left, u get ur win.

As long as you don't make "locked teams" you should be able to break an alliance with the AI before killing the third remaining faction and still get the achievement - that's how I did it at least.

So if you are playing a 3-player game (1 human vs. 2 AI) and you get to the point of being allied with one of the AIs, and you defeat the opponent, you simultaneously get the victory screen and the voice-overs from the allied AI re: "Sorry, this no longer works for us." However, I've found that if you choose to continue the game, you're still allied to the other AI.

Do I actually have to take the step of breaking the alliance (even though it sounded like the other AI was doing it)?

I've found that specifically trying to please on race is absurd at times. One interesting thing I've found is that if you go out and destroy any enemy, key one in particular, the other races will inadvertantly start offering treaties/alliances. I think it's done intentionally by the design team to add a random element to the game. Just focus on your fleet/econ and the alliances fall into place, seemingly by accident.

YES!!!

Here's what you do:
---Make friends with everyone
---Have them attack the Pirates in the center
---Invade their homeworlds!!!

Problem solved...

i love forcing the ai to attack the pirates. they just jump in, turn and jump out...over and over and over.