You can include multiple color themes in your corporate template. Here's my how-to article that discusses several methods for doing this: https://www.brandwares.com/bestpractices/2016/10/multiple-color-themes-one-template/ No script or GPO required.
The second method under the heading Multiple Color Themes: Hacking XML is probably closest to what you want, but the technique in the third section is easier to implement and makes it possible to apply different colors themes to different slides.