PHP Code:
addLocalModifier("once", rangeend, rangeend, "image", "replace", <imagename>, <imagename>);
This post may get deleted but that's my shot in the dark. That _might_ work, but then again, if the GS2 parser evaluates the last two params as numbers, then there's no way to do it with modifiers.
Isn't there some way to access each individual emitted particle?