Want to turn on auto deletion of old voice

Want to turn on auto deletion of old voice mails for a user, rather than for an entire location

We do not want entire locations to have this as their default, but do have a couple of users in the specific location (that already receive emailed copies of their voice mail messages) that would like this functionality, as it's critical that you never get a "voice mail is full" message for them.....and it's time consuming to task someone with going in and deleting old voice mail messages.