check collision of object B from object A

So, currently what I’m trying to do is have a character controller(working on its own) that I can swap the mesh (in a child).

My problem comes when I get to my jumping, I debounce jumping by using OnCollisionEnter, a bool and if statements. But if my script is in object A (player) I cannot use the void OnCollisionEnter to check collisions on object B (mesh)…

tl;dr: How would I check object B’s collision using a script on object A

//attempt 1
	{is_jumped = false;}
void Start(){
col = Transform.GetComponent(mesh.collider);}
    {is_jumped = false;}

all other attempts have equally failed…
edit: using c#

tl;dr; You can’t. Collision messages are sent to the OnCollisionEnter() handlers of the two gameobjects involved in a collision, but are not generally accessible to any third party script.

The solution is to create some sort of custom centralised collision manager, and get objects to update that when they are involved in any collision. This collision manager can then be queried by any other object.