Pages charts, tracking duplicates

I must confess from the brief description it is a little tricky to understand exactly what you are trying to do, but I don't think you can do this in Pages, as the calculation functionality is pretty limited, and I don't think you can link calculations from different chart tables.

You best bet is to create all your charts in a Numbers Spreadsheet and the copy and paste them into your pages document.

In Numbers you can use functions like COUNTIF to add the number of times a string appears in a defined range.

Combine this with the IF function and you could automate what items appear in a third table, which could then be linked to a third chart.

In the example below I have three ranges for three charts. The charts are not shown, but hopefully you will get the idea. The range for the first chart is A2:E5, the second is A8:E11.

I have used the CountIF formula to calculate the number of times each string appears in Chart 1 and Chart 2 the results are in cells B13:B16

If the CountIF value is 1, then it means the item only appears in one table and then can appear in the 3rd Table.

A series of calculations using an IF statement will then define this 3rd table in the range A19:R22, using the CountIF results.

However this is perhaps not the simple solution that you might have been looking for.