Is this the saint you mean in this article:
http://en.wikipedia.org/wiki/Justin_Popovi%C4%87The same article mentions that St. John Popovich knew St. John Maximovich of Shanghai and San Francisco:
In one of those fateful historical moments, fate brought St. Nikolaj Velimirovic, St. John Maximovich of Shanghai and San Francisco and the future saint Arch. Justin Popovich. together in Bitola. The young John Maximovich (a Russian of Serbian ancestry) was the assistant to Fr. Justin Popovich at the theological seminary there, while the Bishop of Ohrid was Fr. Nikolaj Velimirovic.
Is it true that St. John Maximovich of Shanghai and San Francisco was of Serbian origin or not?