So far, my searches and attempts to do this have been unsuccessful.
No team edits one instance of a project simultaneously, they make their changes independently and let source control deal with merging them together.
You can achieve concurrent development with source control. Xcode has native support for source control:
When working on a software project, it can be very useful to use software control management (SCM) to keep track of changes in the code and coordinate work groups.
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When two or more people are working on the same project, source control helps prevent conflicts and helps resolve conflicts should they arise. By keeping a central repository that holds the canonical copy of the software, the source control system allows each programmer to work on his or her own local copy without any danger of corrupting the canonical version. If you set up a system of checking out a file before working on it, you can ensure that two people are not working on the same code at the same time. If two people do change the same code, the SCM software helps you to merge the two versions. You can also look through past changes to see what they were and who made them, which can be a great help in managing the project and in fixing bugs.
