You can't, at least not without ordering directly from the manufacturer and they are going to require an order size in the shipping container range.

The balls you buy from an LBS or mail order supplier are just packaged in bags of 100 or whatever by a distributer who makes no effort to maintain batch identity. If they run out of one lot before a given package is filled they just complete it from the next container. That said, the probability that balls in a given 100-count package are from the same lot is pretty high.

All in all, I think this is much ado about nothing.