Feature Request: Additional attributes for User Segments

Feature Request Summary: 

Zendesk should create new Guide User Segments attributes, including access to custom user fields available in Support.

Description/Use Cases: 

There are other, more granular attributes that would be better for creating User Segments with. Tags are inflexible, as they cannot be assigned programmatically to users in Zendesk. Organizations suffer a similar issue. 

Specifically, in our case, our SSO provider (Okta) effectively resets both tags and organizations when it pushes an update to Zendesk. However, we do map attributes in our HRIS system through Okta to Zendesk. This data is much more helpful in determining permissions than tags and orgs alone.

This feature would allow our team to have a much more robust internal knowledge base, and cut down on the amount of disparate resources we have floating around and need to maintain.

Business impact of limitation or missing feature:

It is difficult to manage knowledge base permissions when Zendesk is used for internal systems, especially in conjunction with tools that have the potential to overwrite or reset data, such as SSO tools. Having access to more granular fields would enable Guide to be significantly more flexible permissions-wise.