The UN doesn’t have any particular claim to the word “international”, except insofar as anything they do is international because the UN itself is international.
Other organisations, or even loosely affiliated groups of nations, can do international things because the word just means something like “between nations”.













If cost is a concern, then just using off-the-shelf bearing balls is almost certainly a good choice. They’re mass-produced in such volume that I doubt you can find cheaper small hardened steel objects with reasonable drag properties