user_header_search_paths or target?

[Joe]

I'm trying to compile my application project, which depends on a
framework project. The application project is not finding the header
files which are included in the framework project. So I have a
cross-reference project setup (separate xcode project files).

I'm looking for a build setting value for use in my application project
that would give me the top level directory of my framework project? I
was thinking I would then include that in my USER_HEADER_SEARCH_PATHS.

Is this the correct way to do it, or should I be using a target of some sort?