Problem
Mentors get newcomers assigned to them equally. They have a parameter to decide if they like to have more or less than the average mentees assigned to them.
However, if you joined a while ago, you might already have a lot of newcomers to interact with or to monitor. Getting more mentees to take care of leads to an overwhelming situation.
Possible solution
The idea is to consider the number of active newcomers a mentor has under their responsibility when assigning them new accounts.