I did my homework. I looked at the documentation and did a Google search but I don't see how to change the default reference type when adding files to my Xcode project.

The default seems to be set to "Relative to Enclosing Group", but I would prefer it to be "Relative to Project". Does anyone know how to set this default to always be "Relative to Project"? Even if it's a project specific preference, it would be helpful to be able to ignore this drop down menu. Thanks!

I doubt there is a way. Go dig through private files if you're that interested.

Otherwise you could make the containing group be relative to the project and relative to the group will probably do what you want. Depends on your situation.