You can make it happen using something called 'Set Analysis'.
Broadly, what you would do is in your first chart, change your measure function to include a set of explicitly selected options that ignores the current selection.
Here's an example:
There are a lot of other resources to help you with this concept. If you can post a sample .qvf, or examples of your formula text we can help with syntax, should you need that.
Consider using Set Analysis to control what happens to your chart calculations when a selection is made. For instance, in chart one, you can use 1 in set analysis to avoid any selections impacting your chart - hence only showing a total. Set Analysis is VERY powerful.
Set Analysis Video:
Check out the Guide: "Script Syntax and Chart Expressions"
There are a TON of resources available.
If you are new - I strongly recommend checking out: