Send SMS to any number (not stored as Lead or User)

Our support team offers support to our customers and our customer’s customer. That said, our customers are stored in our systems as users, but not all of our customer’s customers are stored - nor do we need to. However, we often need to send an SMS update to these individuals. In most phone systems, this isn’t an issue - they act just like any phone where we can send a text to a number, even if it’s not stored as a saved contact. 
We need the same ability for Intercom’s SMS functionality. We do not use the SMS channel for Outbound SMS, we only use it as a support channel.