I like the way the Topps digital apps handle this sort of thing. I could offer the same John Cena "card" to 10 people, but as soon as one accepts, the other nine offers auto-cancel. The app knows the same card was part of multiple offers. It would have helped a member this week who offered a trade to me, and received an offer for the same cards from a 3rd member. I ended up having nothing he needed, but he would have known sooner. I was on my Iowa trip at the time with no access to my cards.
I'm going to reevaluate how I collect after the new year. It's just getting way too expensive for the new stuff. Sometimes I just want to buy a pack, not a whole box or even blaster.