Can a arahant recognize the spiritual attainment of others?

Can a arahant recognize other arahants? Can a arahant recognize stream winners, once-returners and never-returners? Can a arahant recognize the spiritual attainment (and conversely, the defilement) of others? If a arahant is able to recognize other arahants, then we may be able to reliably establish a recognized group of arahants in our time, who can be the lead teachers of the sangha worldwide.