Yeah. A filter could support it but the only tags that relays index are the single letter tags so your suggestion wouldn’t work.
Another option would be to create an interests list like nostr:npub1l2vyh47mk2p0qlsku7hg0vn29faehy9hy34ygaclpn66ukqp3afqutajft has suggested a few times and then you could have a special app that tried to pair users based on the contents of those lists.
Would either require some special relay tweaks or a database though.