Best way to restrict edit access to specific form sections

In the App I am working on there are 3 tabbed sections that an outside user fills out and "submits". On a fourth "Internal" tab my clients have several steps that they take internally using the info filled out in the first 3 tabs. My client is asking that those first 3 tabs be locked for editing by internal users during certain points. I know I can lock edit access to the entire form easy enough, but to break it into parts, the only way that I know of would be to create a dynamic form rule listing what would be 100 fields in those first 3 tabs as read-only when in a certain status or when a certain user is working on it. Is there a better way to do this?

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Chris Swirtz
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