User Sorting by Country

Hey Devs, thanks for the perfect coded plugin. I am just inquiring if there is a way to sort users according to their country in the users page?
Currently users can be sorted by,
Display Name A-Z
Display Name Z-A
Newer
Older
First Name A-Z
First Name Z-A
Last Name A-Z
Last Name Z-A

Can I unset some the above fields? And add custom fields like ‘Country’, ‘Number of Comments’?