Dedicated RAS lines for users

We have 4 RAS lines working in NT 4.0 and granted some users for dial-in permission. My question is, Is there any way we can configure the RAS so that it will dedicate 2 lines or exclusive only for specific users (managers) while the rest of the users use the remaining 2. In short, we would want some users to grant dial in only on 2 lines and not all the 4 lines. Thanks.