Hi, 

I want to create a module where I regroup all of the adding group in followers of purchase and sales.

For example if I create a  requisition, when this requisition goes on the state of "Sent for Waiting approval", one group 1 is automatically added in the followers.

 this same requisition goes from "Waiting approval" to "Approved", one group 2 is automatically added in the followers.

I've created a file -all_notification.py in which i insert

class all_notification(osv.osv):

_name = 'all.notification'

_inherit = ['mail.thread']

_columns = { }

- file __openerp__.py in which i insert all depends like purchase, sale,

-file group.xml where I define all the group.

Then I stuck on it. where i define which group will be added on the followers of requisition workflow for example? Thanks.