Automatically add subscribers to standalone voicemai

Hi,
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.
TIA

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