I have 25 uniforms on my market so far, but I thought it would be a great idea to make a separate set of just the hats for the models with hats, so that those who only need the hats for the uniforms don't have to buy the whole uniform. But this would require defining new UVs and textures for each hat.
I hope you download it if you need it and enjoy.
Product link: https://www.artstation.com/a/46343612