Show/Hide Title Bar based on Non-Native Relationship Field

Content

1. In the Incident Workspace I have a field called Service Account (service_id) which is a System Attribute of Incident that has a relationship with Organization(org_id) as a Parent ID. (Service Account = The Site/Organization for which the Activity will be performed)
2. Organization object has a custom field called National Account(national_account) which is Yes/No field.
3. There is a title bar at the top of my Summary Area of Incident Workspace which says National Account.

I need to display that Title Bar only when the selected Service Account's national_account field is set to Yes.