I believe that teams should be empowered to make decisions and this is critical for product development to be effective and efficient. I agree with the previous post from srg36 that interdepartmental team building events can help. From my experience, I have seen monthly meetings where teams provide updates on projects and their issues and/or share lessons learned so other teams that are experiencing the same issues can benefit from it. One other approach I have seen is where a committee is formed for project review at a higher level where other team project managers and management attend. These meetings have basically two purposes: update management on status of programs and request decisions when teams could not reach consensus. Both examples have been proven to work towards taking negativity out of system in terms of competition and silos.