V-Ray for Rhino: need diffuse shadows through skylight

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So I'm trying to render a scene with a round skylight in the ceiling that has frosted glass in order to diffuse the light coming through instead of casting a direct shadow. I know I can adjust the sun properties to fade the shadows more but that will affect the shadows throughout the scene from other windows and I don't want that. Is there a certain glass material or material property I can use that will diffuse the sunlight that passes through it into soft shadows?

 

Here's a simplified example of the scene mechanics I've having trouble with. I want the light cast on the ground to be more diffuse/blurred: