On Flock presentation we had a screenshot with custom spoke in our Initial Setup for CERN 

https://docs.google.com/presentation/d/1-yPU37DoJH9_cUPPl4HrQ6kyIK9irJG8-ZhOv0peKJc/edit?slide=id.g35f82fa94c8_0_54#slide=id.g35f82fa94c8_0_54

Before we will try to find out how to get this resolved on Initial Setup we should try to find out if Gnome Initial Setup is not able to cover this functionality as it basically duplicates what we does in Initial Setup.