d3 Box Plot Extension: Trouble handling selections

[cahenson2]

I am currently building a custom box plot extension through d3. I'm pulling in my raw data as a dimension and calculating quartiles by group using d3.nest() and plotting the calculated quartiles as rectangles (min->q1 (First rectangle), q1->q2 (Second rectangle, etc.) Essentially, I'm building a plot that resembles this one from d3-graph-gallery but with rectangles instead of the horizontal line.

In my case, the individual data points are student scores and the quartile measurements pertain to the class as a whole. The students are granted access via section access so that they see only their own data. I am trying to have the quartiles for the class as a whole remain while the data points are reduced down by section access to the individual student. 

I've gotten everything to calculate and plot as expected, but I have not been able to prevent the section access from affecting the quartiles. When the section access is activated, the data from the selection drills down to just the single student and henceforth no quartiles can be calculated.

Many thanks in advance for your help/consideration.