more ideas to this, you should be able to help your alliance partners.
example: player-x is attacking player-y of the alli1. player-y doesnīt have enough armies to defend, so his alli partner player-z of alli1 can send him money or armies.
alli partners wonīt be able to attack each other
if you want to leave an alli, you have to click a button and then it takes, for example, 3 days before you are out of this alli, this makes sure that no one can jump from alli to alli only to spy them or so...