The Confidentiality can be set on an item to restrict internal access. See details on how this works
Confidentiality can be applied to an item to restrict access by security groups. This means only the user that creates the item and those users in the security group will be able to see the item and any related files.To set the confidentiality this can be done at either of the time of creating the item or anytime after.
To set confidentiality at the time of creation. From the Create Agenda Item Screen, Click the Select Confidentiality link
From here you can select the Security groups that will have access to this item.
Remembering to uncheck any groups you don't want to have access.
Once the confidentiality has been set you can check or change this under the confidential option from the item menu.