It’s pretty unlikely.
This is what I would recommend:
You could store the numbers as a custom field in Discourse, retrieve it with Data Explorer, and send out the pages through your external service.
Your first step is defining the process. How are you collecting the numbers, validating them, determining who gets messages, managing opt outs, unsubscribes…
There’s a lot of work.
A simpler approach would probably be to step back and build this as an “SMS notification subscription service” where people can subscribe to feeds using someone’s platforms, and publish to that from Discourse.