Hi Jason,
Yes, we tried it and it works. As Lisa, mentioned anything that is not somehow referenced in workspace, is not searchable. Thus the workaround is to create a place holder project and create a linked folder to your common files. This creates that "reference" that allows searching.
Detailed steps would be:
File->New->Project : from dialog choose General | Project ; then give it some name (e.g. Common Files).
Then right click on just added project and select New->Folder , then click on "Advanced" button and choose "Link to alternate location (Linked Folder)", then Browse to directory where Common Files are located. Then Finish.
You will now be able to see all files and search them. It may take couple of minutes to refresh things, depending on how many files are in Common directory.
Martin