I wish there was better documentation for this for Xcode 5 but I couldn\'t find anything decent describing best practices for working with workspaces, so..
In a workspac
This is derived from Tomte's answer. His approach was causing me a Dependency Analysis Error. This is a more straight forward approach and explains why Tomte's answer works:
Note that when using Tomte's approach, when the project is added to Link Binary With Libraries, a project reference is created. This project reference can be found in the Frameworks group of the project.
I'm conflicted as to whether this is a good approach or not. The scheme approach is not much better, in my opinion. I'm actually wondering why workspace project's don't have this relationship by default.
At the very least, this should clear up the magic in Tomte's solution.