How manage a role scheme for 'all projects but one'

Hi,

I have youtrack setup for an organization tracker, it have many projects and all developers, reports and observers can view all other projects issues. Now I need an exception, one project is private for only a group of users. So I need Developer, Reporter, Observer roles apply for all projects but the private one. There's a way to do that without n-1 checks in each role project list? (the problem of this scheme, besides the many checks, is: if a new project is added, all roles should be edited)

Thanks,

Hugo