Non Joinder of Necessary parties

I worked in a company as Accounts Manager and left the company without good terms. One of the my duty in my previous job is to verify the cash vouchers of factory and authorizing the same. The cash vouchers will be prepared by the cashier at factory and signed by the cashier as well as the factory in-charge. These cash vouchers will be sent to my office every day from the factory which is 20 KM away. My previous employer filed a false civil case on me for recovery of money stating that I have misused the cash at factory. Surprisingly he has not made the cashier and factory in-charge as a party in the recovery suit. Now the suit is pending for filing my written statement. I understand that the suit is not maintainable for non-joinder of all necessary parties i.e. the cashier and factory in-charge. Now I request you to advise me whether to 1. File a memo / IA preying the court to dismiss as the suit is not maintainable for non-joinder of all necessary parties. or 2.File a detailed written statement and in the same written statement mention that the suit is not maintainable for non-joinder of all necessary parties. Also advise pros and cons in both the scenarios .