Bar Chart with Aggregate Line Trouble

I would like some advice since I am struggling to build the following in a card.

I have a dataset structured like this:

I'd like to produce a chart like the following:

• Bars: each value where Record_Type = "A" 
• Flat Median line of only Record_Type = "B" records

I would restructure and precalculate median in a dataflow and however I need to be able to use a quick filter on the "Filter column" for the application we are creating. Calculated median will change based on the filter selection.

I've been trying to use the Bar + Line card and trying to create a Beast Mode column through the analyzer creating a constant value of Record_Type B Median so it can be plotted as a horizontal line. I am thinking this way, the median value will be recalculated as the quick filter changes.

 What I am trying to do:

I'm running into the below issues:

• Can't create median aggregation as a Beastmode column in the analyzer
• Can't seem to produce an aggregated constant value as a beasemode column (tried with AVG and didn't work)

Note: Precalculating median in dataflow is not an option unless someone can think of a structure quick filter can still be applied to change the median value based on filtered results. The Record type A and Record Type B records cant be joined together into a flat file structure (Apples and Oranges). The samples above are simplified to demonstrate the trouble I'm encountering.. 

Thanks for the assist!