Exam contains 10 questions, randomly selected from a pool of 17 questions

Amit, probably the simplest approach is what you already have: Four question banks, drawing the number of questions you note.

In the story, add a question draw from Bank #1 to draw 3 of the 5 items. Then add three more question draws for the other items. 

Your challenge will be to report the results that you want to see, or to have the learner do what you want him or her to do based on the results of the questions.

Good luck!