I'm reposting this with just the new information I'm looking for.
I’d like to have the filters show me the aggregate data in the graph. I’d like to try and setup it up so that if I click on two months, I get the average for both of those months, aggregated or combined. This will allow me to do things like look at the dataset by quarter and allow me to do some year-to-year comparisons. I have attached the current view of the workbook and the twbx file.