Thank you so much for interest in our product.
Current, you can set [Map Center] in back-end. E.g: http://i.imgur.com/sfpTB5V.png => http://i.imgur.com/khtX0Da.png but you can not disable another country as your requirement. As you know, Job Map plugin was developed based on Google map so there has some features that we couldn’t customize. Thank you for your understanding.
If you have any other questions, we’d be happy to answer them!