Binary release of -> https://github.com/DeromirNeves/VerticalBar
Releases here -> https://github.com/afallon02/VerticalBar/releases
Add as many Vertical bars to the macOS dock as you want.
- Open > Right click the icon in your dock > Options > "Keep in Dock"
- Rightclick > Quit
If you want to have more than one, simply copy the VerticalBar.app and open it and do step 3-4 above.