Better RRL?

In current implementation of RRL can not been set limits to different responses, set "whitelist" subnets or calculate limits per specified prefix-length. For example my configuration from Bind 9:

  rate-limit {
    responses-per-second 15;
    errors-per-second 5;
    nxdomains-per-second 5;
    slip 2;
    window 10;
    ipv4-prefix-length 24;
    exempt-clients {
      203.0.113.1/32;
    };
  };