The simplest way to create this is a variable that toggles with the click of buttons (click Total Sales, set variable to 1, click Fresh Food Sales, set variable to 0) using the trigger portion of a text object.
Then you have the two charts readily available and set the conditional show in Layout tab to check for the value of the variable.
Please see the attached. I have created a similar Qvw file so that it will be helpful for you to understand. Kindly go through the steps below.
1. Create a variable.
2. Create two text objects with desired names.
3. For each of the text objects Go to Actions --> Add --> External --> Set Variable and in the variable section give the name which you have created in the first step.
4. In the variable value give a different value for both Ex:- 0 and 1 (or) 1 and 2
5. For each of the chart you created go to Layout --> Under Show -->Select Conditional --> Give the values which you are setting in step 3 and 4.
6. That's it when you click on a Text object then the chart corresponding to that will be displayed.
Sample.qvw 163.5 K
If I understand your post correctly, you should be able to use a container.
Below is some information on containers.