Hey @BEEJO, 
Thanks for your suggestion.  Right now, we aren't exploring the possibility of adding this feature. Please understand that we receive a very high volume of feature requests, and cannot realistically implement all of them in the foreseeable future. Thank you for taking the time to share your idea and we look forward to your continued engagement in the Community Hub.

I would also love this feature. Especially from a mountain biking perspective. 

Seems like a massive oversight to be missing the ability to issue segment challenges.

When I thought if it, I went looking for the feature to use with the mountain biking club. Was really surprised not to find it. 

A development shortcut might be possible if a new calendar based Segment filter was made. 

Then set it to segment efforts by friends or clubs to a chosen time frame.