Active DIrectory groups are picked up automatically by the MonoX ActiveDirectoryRoleProvider (see this article for more details
). You can always decide which role(s) will be used by administrators, and set the AdministratorRoles setting in the web.config accordingly (Kristijan's tip is also valid, but requires you add administrators one by one).
For example, in most AD scenarios, system admins are placed in the Admin role. TO reflect this, change the AdministratorRoles setting to the following:
This will allow your AD admins to be automatically recognized as MonoX administrators.