My team would like to host SMS functionality within Zendesk while keeping voice functionality with our number's external carrier. Does Text support hosted numbers?
No, Text does not support hosted numbers. To use SMS as a Support channel, you'll need to purchase a text number. For more details, see the article: Getting started with Text.
You may be interested in porting your existing number into Zendesk Talk. To see if porting is possible for your number, see the article: Porting numbers for Zendesk Talk.