After this, I started building the design system. I started with the atoms, which included colors, buttons, icons and text styles. Because the icons for all brands were a mess, I designed new icon sets for all brands.
After all atoms were put together, I assembled all components (molecules and organisms) together per brand. All dimensions were the exact same, the only differences were the atoms (colours, fonts, etc.). I used all organisms in pages and uploaded both all the elements to Zeplin. Because of this, Zeplin not only contains all pages, but the developers can also find the corresponding atoms, molecules and organisms.