Is there a way to get these words with the same lexical form to combine in the pie chart?
No, I don't believe so. One could export to Excel where one could create the pie chart.
But how do you get the raw numeric data from the chart to put in a spreadsheet? Note: almost 1/3 of the chart doesn't have labels.
You will have to run a Morph Search on the Hebrew word in Logos LXX or LXX Swete and export the ANALYSIS section (though I think it only provides the Greek lemmas).
Note: almost 1/3 of the chart doesn't have labels.
Use mouse-over to see the remaining labels. They would overlap if all were displayed.