Power BI Measure to countrows of related values several related tables deep

Question

I need to create a measure for a card that will count the total number of Question Groups that exist for each person using the tables below.

I've tried the following but it's returning the result 10, instead of the expected result which should be 6. (George = 2, Susan = 1, tom = 1, bill=1, sally =1, mark =0, jason=0)

Measure = COUNTROWS(NATURALLEFTOUTERJOIN(NATURALLEFTOUTERJOIN(People,Questions),'Question Groups'))

What am I doing wrong?

Table: People

PeopleID	Name
1	George
2	Susan
3	Tom
4	Bill
5	Sally
6	Mark
7	Jason

Table: relPeopleQuestions

PeopleID	QuestionID
1	1
1	2
1	3
2	4
2	5
3	6
4	7
5	8

Table: Questions

Question ID	Question name	Questiong Group ID
1	How are you?	1
2	Favorite Color?	2
3	Favorite Movie?	2
4	Sister's Name	3
5	Brother's Name	3
6	What is your birthdate?	1
7	What City do you live in?	1
8	Favorite game?	2

Table: Question Groups

Question Group ID	Question Group Name
1	Assorted
2	Favorites
3	Relatives

A working example file can be obtained here.

Answer 1

A distinct count on the Question Group ID from the Questions table would seem to be sufficient, e.g.

MyMeasure =
VAR MyTable =
    SUMMARIZE (
        People,
        People[Name],
        "Count", DISTINCTCOUNT ( Questions[Question Group ID] )
    )
RETURN
    SUMX ( MyTable, [Count] )