I’m not sure you can actually do that in the real-time renderer. That’s a lot of complex occlusion and refraction, I’d just render it in the path-tracer bc I think that’s the only way you’ll make it work.
That’s not a volumetric cloud. It’s either a heterogenous volume or a niagara fluid sim… The distinction may seem pointless to you but it is very important as all of the volumetrics in Unreal render differently and have different limitations.
To answer your question, if it is a heterogenous volume, there is a project setting for heterogenous volumes called “composite with translucency”