I’m not sure if I understood your question 100%, but I think I know what you’re asking for:
Every document has one active location and up to 3 replica locations. You always read from the active node, from the replicas ONLY in failure cases. This also means that one document only is put on one server only and it won’t be copied to the other nodes (other than for replica purposes).
Nevertheless, I’d argue that Couchbase Server has enough power to even satisfy this use case, because a read operation is very cheap. If this post is very large (1MB or more, which doesn’t seem to be the case here) you might consider splitting it up into multiple docs and fetch them in parallel.
So my advice is: just don’t bother with those one for now, I’d say its premature optimization. Couchbase Server has strong roots in caching and is able to handle up to millions of ops/s.