Here I just created a long torus and put a volumetric point light inside. The deeper the point light is in the torus the more parallel the rays look. I removed all fog, haze, etc, to make the effect more obvious but it's also visible in a normal atmosphere. I put two spheres very near the light to see that they are not affected by it.

The torus is 900 meters tall, 6 meters in diameter. The point light is 890 meters buried inside the torus. Maybe not very practical to include in a scene but I think it's doable, with some tricks. Is this close enough to what you want?