You can create Question Banks at the account-level.
Open Question Banks
With an account selected, click the Question Banks link in Account Navigation.
Add Question Bank
Click the Add Question Bank button.
Edit Bank Details
Type the name of the question bank in the Bank Name field, then click the Create button to create the question bank.
Open Question Bank
Click the title of the question bank to open the bank of questions.
Add Content to Question Bank
Use the tools in the sidebar to add content to the question bank.