sql - How to maintain referential integrity with common great-parent table? -

Let's say I have a table with "group of questions"

 GroupID | Price -------- + ------ 42 | How often do you work 9071 | Other questions ... 

And, for each group's questions I have "question" and "possible answer"

 group | Question ID | Price ------ + ------------ + ------ 42 | 5 | ... brush your teeth? 42 | 89 | ... go to the movies? 9071 | 70 9 ... another question ... ... 

 group | Answer: Price ------ + -------- + ------ 42 | 134 | Many times per day 42 | 135 | Twice a day 42 71 | Once a day 42 803 | Every other day 42 8 | Once a week 42. 666 | Once in a month ... 

Now, in PHP / HTML, I do a complete cross product of one (virtual) questions and to make 42-answer possible replies to a 2-entry table where the user They will select / answer ()

 how often do you do. N / D | 2 / D 1 / D D * 2 | 1 / w | 1 / m | ---------------------- + ----- + ----- +----- + ----- + --- - + ----- + ... brush your teeth? | () | (X) | () | () | () | () | ... go to the movies? | () | () | () | () | (X) | () | 

I know that I want answers (questions, answers, ...) values ​​(5, 135, ...) to insert for teeth
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The question is: answer related to the group of questions in the table "related "What is the method of applying both the question and answer?

(e.g., question, answer, ...) values ​​(70, 71, ...)
Disapproved, because question 709 "Group" belongs to 9071 and North 71 belongs to Group 42.

You type column group , questionID and answer Then two foreign keys, one (group, question id) and (group, answer) on the other.