Need help to update a column when Drop Down List is changed
 

Hi: I have created a workbook with one tab consisting off all data that needs to be accessed by management. The second tab consists of a summary of this data with a drop down list so only one department can be pulled at a time with vlookup formulas pulling the data from the first tab. I have however added a Commentary column on my second tab that I need to also be dynamic and change when the drop down list is changed so commentary can be added to each department selected. Numerous people will access this file and add their own notes. How can I accomplish this?

Thanks
tanya

ADDITION: I have added an example of my spreadsheet to assist you in hopefully helping me. I am desparate for help! Thank you!!!!