Grouping different material items

Hello. I’m new to Nomad and I’m creating a pair of eyeballs. The cornea is clear and reflective using the refraction option but when i go to mesh the cornea, eyeball, iris, etc together the cornea goes back to the original lit (PBR) material that the rest of my project is made of or it all goes glossy. i can’t move this group to where I’d like it and I’ve tried to google similar projects to better understand. Help would be greatly appreciated.

There’s currently only one Material per object.

I’m sure that there are many other methods, but this is how I create a similar eye.

I use the first object to sculpt the main eye and iris.


Add in some color. You can add in all the veins here as well.


And then add in another sphere above the main eye to create the shininess of the eye as well as the refraction. I could also add in the extra bulge of the lens, but at the small size that it’s usually rendered out at, it’s a detail that would go unnoticed.