Karyn Tooke

Adding my plus 1 - there is also the option of 'Role restrictions' in Apps but this is a one size fits all, even upgrading to Enterprise doesn't support our use case:

We have a team that deals with sensitive issues and we want to restrict most agents from seeing those tickets - and to add more complexity some agents aren't assigned to a group which means the 'Tickets in Agents Group' option doesn't help either but they should still be able to access these sensitive tickets. We've also tested changing the Agent setting to 'Tickets in Agents org.' and adding all the required people into those organisations to no avail.