kangaroo bending flower

hi this is a continuation to my last post... i didnt quite find an answer 

ive been assigned a project to develop an installation beside a freeway which has some kind of environmental message. My goal is to create a jungle of towering flower like elements which wilt when polluting cars drive past. my algorithm has the  intended bending motion however i cant find a way to activate the wilting of the flower elements when polluting cars (represented in my algorithm as a box) drive past. im adamant in using kangaroo to properly represent the bending movement of the 'flower' elements so if someone has an answer that will work with kangaroo that will be grreat

i hope this makes sense

can anyone help me?

chris