How can I hide a tab from Dashboard?

Summary:

Initially our sales rep haven't access to employee records in their roles. But we have added a client script on sales reps customer form that needs to retrieve information from the current sales rep logged. And here starts the problems, the scripts always returns an error because the sales rep cannot see employee record information (until this I thought that client scripts execute as administrator).
Then we add permission to view employee records for the sales rep's role, the client script error was solved but a dashboard issue come alive.
Now the sales rep Publish Dashboard show the Setup tab with a link to see all employee records. We need to avoid this, and in the publish dashboard we can lock or unlock a tab, but we cannot hide a tab.