Wait time metric for return call from a voicemail

Hello, in our past call center systems, the wait time for a callback from the time the customer left the voicemail was measurable along with live hold time. I cannot find a method to measure that wait time in Zendesk. This creates an inaccurate wait time metric since the current report only accounts for customers that held live in the queue and does not account for the time it took to call the customer back after they left the voicemail. Please let me know if anything can be done about this. Thanks