For this you probably will need to add some code to your VI to do this instead of right clicking on the chart. You can use the VIs located in the Programming>Report Generation>Excel Specific pane which has tons of stuff for that.
Attached is an example of a basic VI that populates three waveform charts with random data and creates an excel spreadsheet with each chart's data input into a different workbook. This is rough and you can add a lot more functionality if you want depending on your needs. Just take references to all your charts and put them into an array and feed into the for loop.
(Also there are probably better/cleaner ways to do it but this is the best I've got 😛 )
