How to create user from Directory and assign roles for many department(value list) in an application?

Dear communities,

I am very new to lotus development. Now, I need to develop an application to authorize user can manage booking hotel, … for several department which was assigned to him/her.

I have decided to develop a configurable interface for user so that they can manage permission to any department by them self. Department need to extract from their email.

The following is the interface where I would like to develop

https://dl.dropboxusercontent.com/u/33698629/Lotus%20Need.JPG

May be, Im not in a good path. Could you please guide me on how to archive this requirement? I know you guy might have different solution.

Thanks you in advance,

Veasna