User tracking at business unit/department level

I'd like to understand more about who and with what frequency our users are actively using AHA! to drive adoption.

We've been able to download the total users with the date they were activated and the last activity date. However, we can't categorise those users in to the functional areas of our company ie. different products area, technology colleagues.

is it possible to add custom fields to the registration area to capture this data?

Also when a new user registers for the first time, can we customise the login screen for users to enter this data when they register from our own custom drop down list?