You definitely can’t do what you need with the current setup.
You do know also that you are doubling up the amounts here. Boston is being counted twice in this pie chart. Once by itself and then once in the total
I don’t think you should be using a report level filter here. Just make it a slicer if you want to be able to select many different regions
Is there any reason why just keeping it simple doesn’t work?
You really have to have a good think about how the filters are going to work in your model here.
If you place calculations into measures they won’t do anything to the filters in you model, but if you use dimensions (or columns) from your tables they will.
Everything flows nicely when you keep it simple.
I’m really interested to understand why you can’t make it easier?