Control community alias with SSO

Feature Request Summary: 

Zendesk community alias should be controllable with the JWT SSO.

Description/Use Cases: 

I'd like to use customer aliases from our product in our community forums while maintaining real names for our support staff similar to:

https://support.zendesk.com/hc/en-us/community/posts/115000477747-Alias-for-End-User-in-Community

I'd also like to restrict our customer from changing the alias.

Business impact of limitation or missing feature:

We need to store aliases in the customer name field which mean our support staff need to look up their real names in our product from the alias when they want to address the users by name.