OnCollisionEnter problem with wheel

Hi all, i have a big trouble with my cars wheel collider. my car calculating impacts and gives penalty to player. Problem is my impact script working with oncollisionenter and all my child colliders efects from it.

when i try to drive my car and when road plane changes it startig calculate. cant i choos spesific child collider for my rigidbody calculations?

i found a solution like that. put on damage calculator script on the child body collider object and make my calculatings on them. if i try to do on main object, still calculating wheels pressure as a damage.