I am tring to build a sheet like the attached. I can only have one line for address but each address could have multiple work items. I was thinking of creating a data validation that will allow me to select, and deselect, multiple items from the list but I can't get any I have found online to work.

Then I come across the issue of then getting these multiple items to somehow reference a list of values per item and add them up. I have attached an example of what I am trying to achieve. Any help would be great.work type example mym1nd 20121113.xls Or am I barking up the wrong tree trying to do it this way.