He who smelt it must have dealt it...
I have third graders, so the problem is different. But I had one kid who keeps going off about farts. Won't stop talking about it if he hears or smells one. After the rational discussions didn't work, I mentioned that my dad used to say something like, "He who smelt it must have dealt it." And I explained what it meant. Didn't try really hard to stop the laughter and finger pointing at the fart smeller (I mean smart feller). He hasn't smelt anything untoward since.
Translated to junior high , I might mention in a very round about, delicate way, that leaves you plenty of room for deniability, that someone who has condoms to throw around the classroom clearly isn't getting any.
I might say: "Condoms are for preventing pregnancy, and for preventing the spread of aids and disease. Obviously, these particular condoms aren't being used for that. That's a good thing. I commend you for being celibate, and encourage you to continue to do so. That's a wise decision at your age."
Never mind. Your crew might fire back with used condoms.