Halo bright despite gas

I’ve been working on the galaxy (tweaked from this file)
and I’ve encountered a problem. The haloed icosahedron I have inserted in the middle of all these planes (which essentially are transparent and gaseously textured) can obscure each other somewhat, but when it comes to the haloed core of the galaxy it’s always in front. How can I make a bright core that is soft around the edges but will be obscured by the gas?