Dynamic cascading dependent dropdown list

All,

I need your help in creating a dynamic cascading dependent drop down for Column O(Opportunity sheet) in the attached document. I have all the source data in "Work Data" sheet, here product group will have duplicate values so to avoid showing duplicate values in dropdown, i have created a unique drop down for product group in column J (work data), this unique product group is getting displayed in "Opportunity" tab column N.

Now i would like to have the the column O (opportunity sheet) drop downs to display only the relevant product names based on the column N (opportunity sheet) value. Column N values are stored in column G of 'Work data' tab. So for example the dropdown result should be a...

dropdown.jpg

Thanks
Keviv