Mentor Trait?
One of the traits you can buy with aspiration points is Mentor. Apparently it lets your sims mentor other sims when they reach level 10 of a career, but my sims have always been able to do that anyway...
Forum Discussion
I think the Mentor trait relates more to skills than to careers. Unfortunately, only a few traits are affected, mostly creatives (painting and instruments) and I think also Logic and Fitness(?).
