Can Xcode execute pre-build actions for dependency targets when building?

Question

I have an Xcode project with an iOS app target that has a couple of dependencies on libraries that I have included as source code. Those libraries are themselves targets. One of them downloads some files that it needs at build time if they don't already exist. I'd like to do this download as a pre-build step in the scheme for the library target, but I'm finding that Xcode doesn't run pre-build steps for targets that are dependencies of the target it's currently building. It seemed to work a few times and then stopped, and Xcode's build service went down a few times.

Is this expected? Should Xcode be running pre-build actions of dependency targets? Or should I use pre-build actions of the target I'm actually building?