Build Dependency Functionality

I was wondering if the following type of scenario is possible with TC or if not is is something that could be considered for future functionality.

What I am interested in having is a completed build dependency, meaning that a build for A will not start unless there has been a successful build of B (i.e. the last build of B did not fail). I don't really care to have a snapshot dependency either becuase it is not imperative that B always run before A. I just need to know that there has been a good build of B.