Controlling Reflection Intensity

I’m trying to achieve a result similar to [this example] attached an image where the blue and black objects are reflective.

I saw this example: https://threejs.org/examples/?q=mirror#webgl_mirror that uses THREE.Reflector but couldn’t find how to control the reflection intensity (so it won’t be like a mirror) or the reflective object color.

How would you go about this?

Thanks!