Can a WPF application and a VSTO application share a deployment/file storage?

I have two applications that are part of a 'suite' that customers would be getting. One is a VSTO Outlook add-in, the other is a WPF tray application which runs in the background. Because they are distinct applications that are run at different times (the tray ideally runs all the time, while the VSTO add-in is, of course, only run when Outlook is running), they cannot (to my knowledge) share a startup project.

However, because they are basically two tools for the same service, they would benefit greatly from being able to share files (at the moment they both use isolated storage and application settings), and it would be very convenient if they could be installed by the same Clickonce deployment. Is there a way to have (or a relevant design pattern to handle) a single project made of two distinct applications?

I'm very new to .NET, so I apologize if this an ignorant question. Thanks for your help