You are right, the ShowTotals property defines whether the total summary rows will be shown. Currently, there is no appropriate public API that can hide/remove the summary row resulting from each group. It sounds to be a reasonable feature request. This is why I have logged it in our Feedback portal by creating a public thread on your behalf. You can track its progress, subscribe for status changes and add your comments on the following link - feedback item.
I have also updated your Telerik Points.
I hope this information helps. If you need any further assistance please don't hesitate to contact me.
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