Create a thing (voice) for each new voice.
Send the unique id of the voice as the “name” to the API.
Note:
If you don’t like the idea of sending a random id as “name” to the API, you can Set a Slug for each new voice and send the slug to the API instead of the unique id.
Slugs are always unique values and you can generate them based on the real name that the user selected for the voice.