Up to eight other boys have been dealt with by Police Youth Aid.
The victims had been working in Wanaka and were assaulted after they left a bar.
One suffered a serious eye injury. Both are believed to have returned to the United Kingdom.
One 17-year-old boy earned a discharge without conviction in April after impressing Youth Court Judge Michael Turner with his understanding of his behaviour and his attitude to his family group conference plan and community work.
Another teenager's case was transferred to a North Island jurisdiction earlier this year.
A fourth teenager has denied his role in the offending and has a Queenstown Youth Court hearing date of July 17.