The 'Groups' tab on the sidebar allows you to create groups of users and manage access to the content you have created. With 'Groups' you can set up a workflow from a specific case collections and the users that have access to review the cases.

Start in the sidebar via Groups, you now see all existing groups. If you want to add a new group click '+ new Group'. In the example below there already is a case sharing group.

Click the edit icon next to your group to start adding members and content

Adding existing members of an organisation (1) and inviting new users (2) can be performed in the “User” tab.

The different roles are Manager, Editor and Member.

• Managers have all rights including uploading, sharing and payment plans.
  
• Editors have all rights related to content creation and user management.
  
• Members can only see what was assigned to them by Editors or Managers, and have no rights to upload slides or change content.
  

Since you may want to work with multiple case reviewer groups per case review workflow make sure you give your reviewer the 'Member' role' so they can only see the cases assigned to them. Not sure how to change or assign roles, please read Group management

Now proceed to the Collection tab in the menu

You can get an overview of available collections for sharing in (1) and then add this collection in the group workflow in (2)
From that moment on any cases made available in that collection will become visible for the users in the group

Any new content will be visible for the group members when they login, and you can push mail notifications to them about new content using the blue 'Notify Members' (3) email button at the top. This step triggers an email notification to the user. When they next login in the opening dashboard view there is a notification with the details of the notification.

You can read more about assigning content to groups here