Find and Destroy Untouched Objects to Floor

I think this will work:

 // need to reference this in each class
     private void OnCollisionStay(Collision collision)
     {
         if (collision.gameObject == objA) { isHitA = true; } else { isHitA = false; }
         if (collision.gameObject == objB) { isHitB = true; } else { isHitB = false; }
         if (collision.gameObject == floor) { isHitFloor = true} else { isHitFloor = false; }
     }
     private void Update()
     {
         if (isHitA && isHitB && !isHitFloor) { } // do logic
     }

I'm thinking something along these lines, you're obviously gonna have to play around with it to get it how you want. But collision will check itself(the class it's in). So in class ObjA you don't need to reference the object A, just the bool of if A is hitting the others. I just wrote that as an example.