Private Medical Colleges dont participate in All India Counselling. For a seat in a Government Medical College of another State, you should try under All India Counselling. But for a seat in Private Medical College under Management Quota, you should participate in counselling of the State you are interested in for studying MBBS. So for example, if you want to study in Tamilnadu Private Medical College under Management Quota, you should participate in Tamilnadu's Management Quota Counselling conducted by State authorities. These are called B Category seats. So once NEET results are announced, you should register separately for the States you want to try for a seat in. The registrations will be open probably in the month of October. You should keep checking the news regularly for this.