5 vs. 5 battles

Not entirely sure about this.

If you set up the different AI races, you can select your starting relations with them. One of the settings should be 'Team'. I haven't tried it yet (always play with random opponents', but it could do what you're asking for.

I don't know if that works because it still shows that I must destroy 9 civilizations.

Turn on allied victory, then ally with anyone that you don't want to kill.

If you want proper team battles, there are some scenarios that force races into teams. There's one Good vs. Evil vs. Neutral for instance, I can't remember if there's a 5v5 version. Only problem is that you'll be forced to play as Terrans, unless you have the skills to mod the game yourself.

this should be implanted, there should be a custom team option so you can make those kind of teams without having to play a scenario.
that would be great.
if you ally now with 4 IA its 5 vs 1 + 1 + 1 + 1 + 1 wich is no fun, you win no matter what.

Where can I do that?

It's on the screen where you select your map type and the planets settings, it is down the bottom left hand corner, there are a few checkboxes make sure Alliance is ticked.

Hope that helps

I thought there was a way to set up teams between the AI's. I may be mistaken, can you not do that like you could on Empire Earth or Starcraft? It just makes it void if you post it to metaverse.