Good on you for running the club and program for the youngsters.
No need to come there. I can tell you how we did it. We spend $$$$$$$$. and bought A LOT of rimfire ammunition. We have it stored safely in several locations. We top it off every year. A shortage like this will just mean we buy a little more next year than usual to top off.
At the other club, we buy about 50k rounds every two years for members to buy off the club at cost plus a very little profit so that when we repurchase we have enough to account for price increases. Members can buy by the the box, brick or case.
I guess we just like to shoot and admittedly, or clubs have lots of money.