I know this may end up getting closed quickly. I could not find this in my searching through APIs. And this is probably a very simple question but here we go...

How do you store data on a google application you create in which you and others in a specific group or more specifically the people who can edit a specific calendar, can reach this data?
Person A,B,C have read/write access to a calendar, and lets say they want to co-ordinate information. I want this information to not be accessible to modify by all 3 though it is not stored in a calendar? (Though I thought about just creating an event in 1900 and then that fullfills that, but at the same time is a very hack way to do it)

I would appreciate any insight you can give me when it comes to data handling in google applications, I am very new to it, but have been looking into it.