If I understand it correctly, you are looking to have leaderboard for specific country in which you want to show the rank of given user and few entries above and below user rank in that country leaderboard.
This feature looks quite interesting however direct support of this method is not available. We will love to have this in our product release and will put this in our backlog. We will update you once that method is available.
For solution prospective, you can build your own leaderboard using Storage service and writing query on top of it using MapReduce and Query interface to fetch target records and leaderboard. Some useful links http://api.shephertz.com/tutorial/Saving-App-Data/?index=storage-data