How to store AD GROUPS in Windows Auth and use them in code
 

I 'm working on an intranet system
And i want to make use groups/roles on Active directory
Which way would be the best to go?
How can i store the AD groups to validate users in my code.
I don't want to hardcode the GROUPS/ROLES in my codebehind or page.
I know i can perform authorisation in web.config baed on the page or
folders.
For example if i want to generate a menus structure based on who is logged
in etc and also perform
...
Are there ways i can store the groups and selectively call the groups and
check in my code?
Any ideas.