[Plugin: ALO EasyMail Newsletter] Adding custom fields but not display them

I know the custom hooks file enable add custom fields to the newsletter subscription.
I would like to use custom fields (like phone etc) but only for the admin, not fot the registration form. The idea is for a small association, they would really use this to manage their contacts and stop having 25 excel files.
Would it be possible add in the custom hooks additional fields the option to not add those fields int he subscription form?
That is a suggestion 🙂

http://wordpress.org/extend/plugins/alo-easymail/