Restricting Access to Specific Individuals

A user is trying to restrict read access to only specific individuals but it isn't working.  The community default i that logged in users can read anything.   She clicked on Manage Permissions and added a group that she wants to be able to read the asset.  She doesn't want everyone to be able to read it.

Can you do this?

We tried setting the lifecycle state for Approved assets to Over-ride community settings, but this prevents everyone from viewing the asset, even people she adds using Manage Permissions.

How can you restrict an asset so that only certain people can see it?

Thanks,