Type-ahead for only specific directories?

We have Directory Assistance enabled. Is it possible to have type-ahead enabled, but exclude a specific directoy from type-ahead? Is type-ahead all or nothing?

We have 3 directories in DA, and would like the type-ahead only on the first 2.

Subject: Type-ahead for only specific directories?

Off the top of my head, I’d say do not give users access to the 3rd directory and the type-ahead on it should not work for them. But mailing will still work if they type in a name that matches, because the router/server does have access to it.