There is another higher-level project hosted on a different RTC server than ours which will be generating some epics/stories for my project. Of course we want those to appear in our RTC system for planning and tracking. We'd like to avoid duplicating all the epics/stories/tasks/defects in both RTC systems. What do ya'll recommend as a best practice?

1) is there a way to create a work item in one RTC system and have it mirrored in another?
2) should the higher-level project have only our epics, which are manually-created copies which simply refer to the authoritative/active one in my RTC system, and the stories/tasks/defects exist only in my RTC system?
3) something else?

Thanks in advance for any suggestions!