Add check to customers in backoffice

[paquitochocolatero]

Hi, I need to add a value asociated to customers to diferenciate some of them inside a group.

What i like to do is add a checkbox in backoffice inside the form that shows customer information like Name, email, Group...

 

I want to use that boolean field in cart to remove taxes for this special customers.

 

Someone could help? 

 

Thank you and sorry for my english.

[paquitochocolatero]

Hi ndiaga, I already have configured the tax rules. What i need is different, i need to apply the exemption to several customers wich belongs to a group.