Hi you can run one notebook from another and pass value as widget:

run_notebook(notebook, timeout, widgets_value)

Here is more info https://docs.databricks.com/notebooks/notebook-workflows.html

You can even run them in many processes simultaneously:

    from multiprocessing.pool import ThreadPool
    my_params =  ["Eu","JP","APAC"]
    pool = ThreadPool(4) # match cpu cores here
    pool.map(
        lambda my_param: run_notebook("my_notebook", 3600, {"my_widget": my_param}),
        my_params)