Formula result on same row with grouping

Old question, but answering for posterity.

You can do this by hiding detail rows and grouping by the field you want the summary formulas by, eg: Owner. Also toggle off Row Counts.

Here's an example I made that summarizes all opportunity data by Account name.

When detail rows are toggle on, you'll then see multiple rows for each account grouping, which is what you don't want based on your description.