How to use the numbers widget - by group?

Is there a way to create numerical summaries of a single board - by group? If each group is a month, then I want to see a a specific summary per month.

For example, in the image below, I would be interested to see the average “Budget” per month (10760+10900)/2, and the median “# of people attending” per month (1210+385)/2.

Even though there are only 12 monthes a year, in my real use case, a single board can have much more groups than 12. So I am interested in displaying summary statistics for groups easily.

The solution I will probably use will be simply exporting the board to Excel - then use some manual filtering to leave only the summary rows, and then use those for calculations.