Using Intersect function

Armed with the suggestion for disconnected tables and some head scratching time, I think I figured this out.

Solution was to clone the data table (QuestionA and QuestionB) and give each of them separate slicers for the questions and response options. I use DAX to create calculated tables based on the current selection for each, and use Intersect to get the numbers I need. The calculation works like this:

• Numerator: everyone who chose selected question/response options for BOTH questions
• Denominator: everyone who chose selected question/response for A and ANY response for B question

Here's the DAX: 

PctRespAthenB = 
    VAR ThisResponseA = CALCULATETABLE(
        DISTINCT(QuestionA[Respondent]),
        ALLEXCEPT(QuestionA, QuestionA[QuestionRoot], QuestionA[RowIndex])
    )
    VAR ThisResponseB = CALCULATETABLE(
        DISTINCT(QuestionB[Respondent]),
        ALLEXCEPT(QuestionB, QuestionB[QuestionRoot], QuestionB[RowIndex])
    )
    VAR AllResponseB = CALCULATETABLE(
        DISTINCT(QuestionB[Respondent]),
        ALLEXCEPT(QuestionB, QuestionB[QuestionRoot])
    )
RETURN
   COUNTROWS(INTERSECT(ThisResponseA, ThisResponseB)) /
   COUNTROWS(INTERSECT(ThisResponseA, AllResponseB))

And here's how it looks in a rough version of report. I will swap in text for questions & responses later but you get the idea.

I tested this against some crosstab matrices I created before and the numbers lined up. Nifty that you can even select multiple response options to essentially bin the data.

Make sense? Any suggestions?