Different kinds of Alliance

Currently alliance seems to have some silly issues, like handing over end game tech to an ally to win, creating such a large alliance that you immediately win an expansion victory, or winning by leaving an alliance because victory conditions scale depending on the number of allies you have.

I would really like to have the option of segregating victory types from an alliance. 

In simpler terms, I would like to be able to create a "defensive pact" or military alliance but NOT  have my allies worlds, science, etc from impacting my victory conditions. I have my victory conditions, they have theirs, we still compete in those regards- but we can support each other militarily.

I would like this to be in addition to the current alliance type if I would like to use it. Since we don't have the ability (that I have seen, at least) to bribe another player into war against someone else, or entice them to join a current conflict without creating a full blown alliance, I think this would be a sensible addition to the game.