There could be a way to make teams or Clubs. In those Clubs you share the Code and people can join.
Like this there could be a tab at every track where you can see the times of other people in the club. So u can race against friends without having to make own maps. There also could be a limit to how many people can join (10 or sth like that). Also could there be a feature where everybody in the club can select 5 (just an example number) maps and now they will be displayed under the standard tracks. Now there is for every member a track which fits there skill.