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)