Alert notification sent to the user

We have a monitoring of our storage system in place with notifications sent to the team on the health of the storage cluster. I would like however to be able to monitor and send notifications on disk quotas to the users who reach 90% and above.
I’m using Prometheus for keeping the data and I’m able to create alert without any problems, I’m wondering however if it’s possible to send an email to the specific users based on the user label. Let’s say John Doe has reached 90% of the user, I don’t need admins to know about it but I would like to let John know about that. Is it even possible to dynamically define the recipient of an alert message?