Xpresso iteration and getting index of objects upon object specific event

Hi all,

I have a bunch of objects being iterated through to check if they are colliding with a plane,
I’d like to get a read-out which indicates when a collision takes place and the index of the object(s) colliding. Is this possible with xpresso?
Please check my test scene:
https://dl.dropboxusercontent.com/u/24304389/step2time_collision_v3.c4d

I have come across this problem in the past, what exactly does the iterator output, does it have a format? list?
If it was like a proper for-loop then we should be able to do things like interrupt,
execute things while the loop is going..
Am I right in thinking that xpresso nodes all execute once per frame, and an iterator exectues x amount per frame, so its impossible to do things while in the actual loop?