private boolean shouldRemove(NodeCandidate candidate) {
        var currentGroup = candidate.allocation().get().membership().cluster().group();
        if (currentGroup.isEmpty()) return true; // new and not assigned an index: Not needed
        return currentGroup.get().index() >= requested.groups();
    }
Unretire nodes that are already in the correct group when the group is deficient.
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/provisioning/GroupAssigner.java