Dynamic light that ONLY process shadows

I’m trying to give the illusion that a sphere is under 4 spot lights by casting four shadows. I have hundreds of spheres and the lighting is VERY costly.

When turning my spotlights off, the game runs smoothly. For curiosity I also tried the lights on with shadows turned off and that still ran slow. I can accomplish all the lighting with one light but then I lose all my shadows.

What’s a clever way to get around this problem? Can I ditch the lighting processing while still keeping the shadows?

I solved my own issue at