Automatically add subscribers to standalone voicemai

I am using Asterisk 13 as a standalone voicemail. I have it connected to a mobile phone network with SIP.
The question I have is, is it possible to have new subscribers automatically populating in the sip.conf and voicemail.conf?
I currently have to manually add subscribers and this will become laborious as the amount of subscribers increase.
Any help or advice will be greatly received.

That’s possible with AMI, but a non-trivial amount of programming will be needed.