As I read und understand this, I also think your requirement is very similar to the description from @t00thl355.
While he describes in the idea to use the button for the overview in a different way, you want to keep the overview as it is - and just want to scroll through the legs of the tour?
As I understand we are talking about this.
Please give us an idea about this. Something like this, that you have two buttons to scroll? Or a list view? If list-view, may it hide the map? Something complete different?
Please check also here again. Robin has put the suggestion from @t00thl355 to the Planned Features, so users can give more ideas and usecases - and can vote.