I dont know if that specific way has been tried here.
We do have two groups that i personally are involved in that have taken mentorship seriously and as you mentioned boths groups participation has waned recently or slide behind the scenes.
They are:
The abuse support group sancturary, and the H&Hsubs club. Both discussed and promoted mentorship for various reasons.
Of course thier is the sites "Tasking society" which in a way promotes mentorship as well.