When you enter into "Link", click on the settings icon in the upper right hand corner.  Once you do that, you will see a dropdown tool box.  Click on manage Clients under Firm.  This will show you all of your clients.  Search the client you want to "hide" and click on "Mark as Inactive" in the action column.  That client is now hidden and you will not see them on your client screen.

Hope this helps you out.