How to choose a unique contact in android

Hi guys, I am stuck on how can I select only one contact that is repeated in the contact list. For example, if a user has a number (xxxx-xxxxxxx) twice in their contact list, I would like to select it only once. In short, pass any method GROUP BY NUMBER

in the request. I am using below method to select contacts

Cursor contacts = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, null, null, " DISPLAY_NAME ASC");