pass hostnames to --option builders and have it pick up the rest from /etc/nix/machines

[teto]

I would like to set remote builds manually, i.e., on a per build basis because my decision process to buiid remotely is too complex to be described in nix.
I usually prefer to build locally except when I am on the move (on battery) or if I am already building stuff. It also depends on what I build etc. Also the state of my builders is erratic, one is often down or the other busy etc.
Basically I have configured 2 remote builders that appear in /etc/nix/machines.
Now I would like to refer to them by a name or their hostname and have nix pick the configuration from /etc/nix/machines instead of having to specify every parameter on the command line as explained in https://nixos.org/nix/manual/#chap-distributed-builds.
Like
nix-build -A myPkg ~/nixpkgs --option builders 'toto'
with /etc/nix/machines as nix attributes ?

  nixosMachine = {
    hostName = "nixos.totoBuilder.net";
    sshUser = "tata";
    sshKey = "/home/teto/.ssh/myKey";
    system = "x86_64-linux";
    maxJobs = 2;
    speedFactor = 2;
    supportedFeatures = [ "big-parallel" "kvm" ];
    };

or just pass the nix attribute in the builder ?

[stale]

I marked this as stale due to inactivity. → More info

[teto]

still relevant to me