This is an area of extensive research ("anti-collision") and a solved issue. Even decades old protocols support interacting with a plurality of tags simultaneo

This is an area of extensive research ("anti-collision") and a solved issue. Even decades old protocols support interacting with a plurality of tags simultaneously. https://en.m.wikipedia.org/wiki/Singulation https://en.m.wikipedia.org/wiki/Singulation (Edit: added wiki article discussing anti-collision, which specifically references grocery examples)