You cried for it so we did it
Don't know why you may need local cubemaps? https://community.arm.com/graphics/b/blog/posts/reflections-based-on-local-cubemaps-in-unity
Doc:http://doc.babylonjs.com/how_to/reflect#using-local-cubemap-mode
Demo: https://www.babylonjs-playground.com/#RNASML#4