Restrict Visibility of Address List

Hello there,

I have created a custom address list, and currently it is visible to everybody.

Now I'm looking for the best way to restrict visibility of this AL to only a small group of our users.

Do I have to create 2 address book policies and assign the appropriate ABP to each user?

- one ABP including the custom AL

- one ABP not including the custom AL

Or is there a more straight-forward way to hide the custom AL from the majority of our users?

Thanks