It's a question of picking..
You can pick by comparison or by evaluate or random or pick all
so on object clicked
if object.animation = 3 - set animation to 1
system pick all objects
system pick random object - set animation to 2
well something like that, but it would be much easier if you were a bit clearer on what you want..
Should the animationchange be random, should the objects picked be random, how many objects should change animation, are the animations multiframe or could you just use one animation with frames, etcetera..