How can I highlight only intersected area over two objects (in my case that is STL file) in Three js?

Questions
,
1

So far what I did:

const pointer = new THREE.Vector2();
const raycaster = new THREE.Raycaster();
raycaster.setFromCamera(pointer, camera);
const intersects = raycaster.intersectObjects(scene.children, true);
for (let i = 0; i < intersects.length; i++) {
       intersects[i].object.material.color.set(0xff0000);
}

The above code can highlight the whole object instead of just overlapped area. See imageScreenshot from 2021-10-15 00-19-51

I want to highlight the selected red area portion (which is intersected(overlapped) between two teeth) in the uploaded image.!

Screenshot from 2021-10-16 11-46-35|316x98