How can I retrieve the values from Found In (aka Releases defined) in order to populate a custom attribute

My client has the need to add a custom attribute "Release ID" for a defect.  I would like to populate this field with the Releases that are currently stored in the RTC built-in Found In attribute, versus having the customer (or me) have to manually add new Releases in 2 places.

Is this possible to populate the new custom enumeration field automatically/programmatically based on the Found In values?

Thanks for you help!