region-management

With WPF Prism can you prevent two modules from trying to use the same region simultaneously?

Here is the overview of what I am trying to do. I have a region in the shell that is used for application modal dialogs. When a module wants to launch an application modal dialog it loads a custom Lightbox control into the region and fills it with the content I want to display (warning, wizards, etc). I have the region defined in the s...