At the moment the best way of allowing multiple users to update a project is to save your project file in a location that’s accessible for all users who need to edit it.
You can then use the password protection facility that MindGenius has built in to control who can save edits to your file.
Alternatively, to stop unauthorised people from accessing the file in the first place you can set permissions against the file itself in Windows to control precisely who can open the file.
An alternative to using Windows in this way is to use Microsoft SharePoint. As of version 4.2 MindGenius has supported SharePoint’s version control and check in/out directly within the application, meaning you can store your maps in the secure SharePoint environment and yet still access them directly through MindGenius.