I am going to be running a cron job that pulls in a number of images in from other servers and need to store these in a central location that SilverStripe can use and protect. These images are only to be accessed by the appropriate groups and thus I need to use SS to gate access.

First, where and how should these be stored so that SS may do this?

Second, how do I set up an authentication form that will allow these groups to login? These accounts are wholly controlled from within the CMS so I don't actually need to allow users to sign up from the outside, just simply login in order to access these pages that then pull out these protected images.