post https://medchatapp.com/smschatapi/external/orgs//passthroughSmsMessages
Posts a "passthrough" SMS message to the recipient(s) from a MedChat system number. Messages sent using this endpoint will not be visible in the Texting area of the MedChat app. Replies from the recipient will also not be visible in the MedChat app. This endpoint is throttled up to 250 messages per minute.