Design question

I have a custom entity called "Survey" which has 200 attributes ( 200 questions).

I need to report by category ( there are about 20 categories).

For example:  Questions 1-20 belong to category A.  Questions 21-50 to Category B.  Question 51, 61, 71 to Category C. 

How do I model it in CRM 2011? 

I am thinking of having 2 entities ( Category and Question), set 1:N relationship between Category and Question.  Finally set 1:N relationship between Survey and Question.

Will I be able to report survey with their questions by category?

Any suggestions will be greatly appreciated.