[Hampshire] Users & Groups within Pygtk applications

Hello all,
This is a little bit specialist but hopefully relevant to the people on this
list.
I'm currently developing my first major pygtk application and it's come to
the time to make decisions over users & groups for the application, the
sofware itself is a radio station playout system, of which has multiple
users and groups. Ie for all the dj's at the radio station.

The system will have jingles, beds, adverts on it and some will be sharable
between different users and groups.
My question is along the line of how to store details about the users &
groups, do I use the linux system of users, home directories and the like or
do I invent my own system within pygtk?
The application is also being ported to windows, so there will exist some
compatibility issues.