Digital Identity proofs without revealing single identities

Hello DID team,

using DIDs for voting is nice. But if there are real people behind these DIDs then annonymous voting is not possible if you are signing data with your key. I googled a bit for Zero-Knowlege Signatures and got some hits. But I am too far away from this topic to filter garbage from this list.
Use case: You have a group of n DIDs and you are only interested in votes from this group, while votes from other groups woudl not be counted. A vote should be provable belong to the only allowed group without knowing the voting identity (person) behind the vote.

Is this wishful thinking or a real thing?