Length of service - Groups

Summary

How to group length of service

Content

Hi, I'm doing some reporting & dashboards and was looking for a way to group the years of service into groups.  i.e. number of staff in <2 years, 2-4 years etc.  Do I need to add a new calculated item or is there a function to group them when I add a graphic view?

Thanks 

Version

11g Release 1 (11.1.1)

Code Snippet

ET VARIABLE PREFERRED_CURRENCY='User Preferred Currency 1';SELECT
   0 s_0,
   "Workforce Management - Worker Assignment Real Time"."Grade"."Grade Code" s_1,
   "Workforce Management - Worker Assignment Real Time"."Grade"."Grade Name" s_2,
   "Workforce Management - Worker Assignment Real Time"."Worker"."Employee Gender" s_3,
   "Workforce Management - Worker Assignment Real Time"."Worker"."Employee Name" s_4,
   "Workforce Management - Worker Assignment Real Time"."Worker"."Person Number" s_5,
   DESCRIPTOR_IDOF("Workforce Management - Worker Assignment Real Time"."Worker"."Employee Gender") s_6,
   "Workforce Management - Work Relationship Real Time"."Work Relationship"."# Of Years Service" s_7
FROM "Workforce Management - Worker Assignment Real Time"
WHERE
((DESCRIPTOR_IDOF("Workforce Management - Worker