Thanks for your post.
Pie charts are not designed in the current version of FileMaker to allow for multiple fields. When designing a pie chart the x axis will function as your field labels, and the y axis functions as your values. While the option is present to add multiple fields to the y axis only the first field added will be drawn into the pie chart, thus only reflecting the values from the first field.
As an example I created a simple test file and added 4 record for years 1977-1980 with 3 value fields of random numbers. In a pie chart only the first value field was listed. The pie chart then totaled the values for field 1 across the 4 records and assigned the appropriate percentage for each value from the total.
As such, tracking multiple fields within the same record would best be accomplished via one of the other chart types. Each of the other types allows for multiple field tracking by adding extra fields to the y axis on the charts.
If you would like to request this feature for a future release please fill out our feature request form at the link below. I also suggest listing a real life example of how it would be useful to you as part of the request to give our developers a full scope of how it would be used and why it is beneficial.
You may be able to get what you want if you restructure your table so that you do not have multiple fields.
Split your 7 different fields up into 7 different records--each record with additional fields to identify the record correctly.