How do I link two or three widgets in operations dashboard such that a change in one changes the figure/display in others? For example; I am developing the dashboard for a road maintenance agency. I have a widget that displays the amount of money paid to the contractor so far maybe according to milestone, and another widget that shows the total cost of the project. How do I subtract the amount paid so far from the total cost of the project so that the balance will automatically display in a third widget.