create a selection of questions based on taxonomy

An instructor when creating a question would like to set the primary and secondary (maybe tertiary) categories of question, via a metadata tag:question:
Also to have fields to store data such as quality of question and when last the question was used (To be filled in manually)
When setting up the quiz he would then like to add questions based on a keyfield i.e. do a search and select the questions to be inserted.
But once the quiz has been set up, to also find out how many of the questions selected also belong to another category.

For example:
Question: Clinical features associated with a moderate to high risk of renovascular hypertension include all the following except
Option1: abrupt onset or severe hypertension
Option1: hypertension resistant to 3-drug therapy in a compliant patient
Option1: onset of hypertension after the age of 30 years and before the age of 55 years
Option1: hypertension in infants with an umbilical artery catheter

Metadata fields:

• Used: September 2006

• Quality: All gave correct answer

• Primary Classification: Renal, Cardiovascular, Clinical Features

• Secondary classification: Renovascular Hypertension