Feed unique values into effect parameters of duplicated pre-comps?

Question

I have a pre-composition with some fairly complex particle systems that I would like to duplicate multiple times in a final comp.
The trick is that I want to apply a unique "position XY" value to the various effects inside each precomp instance.  I already have the values chained together with the pick-whip inside the pre-comp, so all the "position XY" values can be moved as a unit.
Is it possible to feed unique effect values down into the stack of pre-comps using expressions or some other trick?

Answer 1

You can't have one instance of a set of precomps that renders differently when used multiple times.
You would have to create multiple sets of those precomps and put different values in each. You could do this by saving the set of precomps as a project then importing it multiple times. Or there's a script for duplicating a comp heirarchy here: http://aescripts.com/true-comp-duplicator/
Before doing that you could use expressions to feed a random value into certain properties so they would automatically be different in each duplicate set. For example this would put in a random XY position value:
seedRandom(1,true);
x = random(0,640);
y = random(0,480);
[x,y];