Password is email extension only

I am wondering if this plugin (it is okay if it is the premium version) has the capability of having the password look only at the email extension. I need anyone that has an .edu extension to be able to access a page. I realize that this isn’t very secure but that isn’t a big issue. The client wants it this way and I can’t find any type of plugin that can do this. Please let me know. Thanks.

http://wordpress.org/extend/plugins/password-protect-wordpress/