Ability to point Text Analytics Roles to custom field

We’re starting to use Text Analytics more, and we’re running into a bit of an issue when trying to view the NPS details by Role.

We use a custom field for Role because we are mapping it over from the Account Related Contacts in SFDC where the role field is multi-select whereas the OOTB GS Roles are single select.  

We’d like the ability to point the Roles option to a custom field instead of the OOTB field.