Have a look at this thread for what you can do (although you can’t do exactly what I think you want to) in regards group workouts. In particular the video from GPLama within one of the posts is informative.
Regarding Climb Portal for group/club/events - not at the moment. This is from their FAQ.
Q: Will event organizers be able to use the climb portals?
A: At launch, events will not take place within the Climb Portal. The only way to take part is to join from the homescreen or turn into the portal from the route you join.
So possibly in the future?