Block Out Going Data | Window Server or Machine

I have a window Server R8. I have WAMP installed on it, I want to Block Outgoing data from the server in any form, It can't be transferred Through FTP Protocol, neither Through email attachment neither Through any means. the reason I have some sensitive Codes that needs to have some work done, I can't Transfer these codes to the Freelancers, neither do i want that they should be able to do this while they are working on my Server. There could be other Methods But i am sure this should be achievable through Firewall.