I have a data set with X values ranging from 0 up to 300-400, the Y values are an AVG of the values for the given X.

I am interested in the values at the low end of the scale, say 0-10 and want the X values 10 and greater to be grouped into a single category then averaged.

I do not seem able to achieve this in a Chart View, but I feel it should be possible. I tried to add a report formula but what I am looking for did not seem possible.

I DO NOT want to simply filter off the values >10, I want a single entry for 10+ that includes all values 10 and above.
I want to avoid building a custom Query Table to achieve what seems like a relatively trivial grouping of values, the data is already coming from a Query Table and the data needs to be grouped in multiple ways for different charts within a dashboard.