Help Segregation of instructions to each rope at the time of collision

[NakanHogeri]

I'm currently trying to change the color of two Obi Rope in the same Solver at their own timing when they collide with other objects.

I pasted the script below on each rope and tried it, and when one rope collided with another object, the color of the other rope was the same.

Code:

private void Solver_OnCollision(ObiSolver solver, ObiSolver.ObiCollisionEventArgs e)
    {
        foreach (Oni.Contact contact in e.contacts)
        {
            if (contact.distance < 0.025f)
            {
                    ChangeColorDark();
            }
        }
    }

Obi version 6.0, Surface-based collisions are enabled on each rope.

If I had two Obi Solvers in the scene and one rope as a child object of one Solver, the current script would work, but it would be very costly.

I would be very grateful if you could let me know if you have an elegant solution.

Thanks.