If a Pope/Patriarch ever visits or is invited to a service already with H.H. Pope Shenouda III attending, as shown here http://www.youtube.com/watch?v=wypbNYD6z2k&feature=related
(The Patriarch isnt even Oriental Orthodox, so is he allowed to serve in the liturgy?), do we say papal hymns only for our Pope, or for both? Also, you know when only the Pope can hold a staff and no bishop? Would the visiting Pope/Patriarch be allowed to hold one, also?