front end - Use different kernels for different Notebooks

I know that the command LaunchKernels[] starts up four kernels on my machine:

LaunchKernels[]
{KernelObject[1, "local"], KernelObject[2, "local"], 
 KernelObject[3, "local"], KernelObject[4, "local"]}

I also figured out that the command SetOptions[EvaluationNotebook[], Evaluator -> "xyz"]; should then set the given Notebook to be evaluated on some kernel "xyz", but I cannot find the right syntax for this "xyz" to refer to for instance KernelObject[1, "local"]. What should I write there?

EDIT

This is the relevant command: FrontEndExecute[FrontEndToken["ModifyEvaluatorNames"]]. Create a couple Kernel names and evaluate in parallel.

Answer

LaunchKernels launches subkernels used for parallel calculations. These are not meant to and cannot be set to as the evaluator for a notebook.

To set the evaluator for a notebook, use Evaluation -> Kernel Configuration Options to set up a new kernel, then use Evaluation -> Notebook's Kernel to assign it to the current notebook.