Drupal Employee ID for og members

Our organization is developing an intra net for our company each group is a separate department. Every thing is accomplished through OG module. We need module or views etc., so that each employee in each group has a unique ID number beginning from 1,2,3...etc and so on. So that we will be able to assign task for the day through ID Eg: Employee ID Task to be completed 1 Invoice preparation 2 Document filing etc., Each ID corresponds to a user in group (OG). This ID should also be visible on user profile