wi fi - Which Android system file(s) should I change to connect only to specific Wi-Fi hotspots

I would like to make change in some file under the root so that Android on my device be able to connect only to specific Wi-Fi hotspots by their names and be disable to connect to all others hotspots. I mean to specify a list of the allowed hotspots in a file. I'm interested only in changing a file or files under the root and not in a program/app or changing of settings.

Which file should I change and how to?

If I make my device rooted, then add specific networks in data/misc/wifi/wpa_supplicant.conf and then switch update_config to 0, new networks are not added to the file, OK. But I still can connect to any network by typing its password manually. So how to disable this? Or how to change graphic interface to be disable to type the password manually?

ps. It's not a duplicate of Only connect to certain Wi-Fi networks