How to easily bring 80 MySQL users into ProxySQL?

I am setting up ProxySQL in front of a Percona MySQL server with 88 user accounts. I don't even know most of their passwords. Passwords are stored in MySQL as hashes but are stored in ProxySQL in plain text. How can I easily bring in all 88 accounts into ProxySQL at once? Or is there a pass-through authentication switch I can turn on?