Hello Mike,
Thank you for reaching out to the Gravity Forms support forum. I understand the importance of integrating Gravity Forms with HubSpot in a way that supports your business units. Unfortunately, the current version of the Gravity Forms HubSpot Add-On does not natively support sending form entries to specific HubSpot Business Units.
You can check this thread as well where you will find an official reply
Therefore from here, you can learn more about how to associate your assets with business units within your HubSpot dashboard.
Thanks