Custom alert about learners waitlisted status

Summary

Is it possible to build a customalert to notify learners about their waitlisted status

Content

Hi there, 

We have the requirement to build a custom resource alert that would reach the below objective:

"Waitlist Alerts - Employees to be notified of details for the offering if they join the waitlist and notified if they are moved from waitlist to a booked/available seat in the offering"

Has anyone built something similar before? I am trying to understand first if the resources are available in the filter. I noticed in the API documentation that maybe assignment status can be used to pull learners, but I don't see specifically waitlist status mentioned.