Hide certain users from login screen greeter (Ubuntu 19.10)

Even though Its a duplicate of How do I hide a particular user from the login screen?

I have just tried it whether its working or not in Ubuntu 19.10 Fresh Install

It worked..

sudo -H nautilus /var/lib/AccountsService/users/

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I have a, b, c, & d user accounts while bullet is my own account (Admin)

I would like to hide user a & c

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so open file a and c and make SystemAccount field to true.

[User]
Icon=/var/lib/AccountsService/icons/a
SystemAccount=true

then logout and login

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the same way I have hidden the Admin User also

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