Q: A bishop I know mentioned that when a group is traveling on pilgrimage together, or a presbyterate is on retreat, all in another diocese than their own, they are to use the name of their own ordinary in the Eucharistic prayer and not the local ordinary. This was news to me, so I wanted to see if you could confirm or not.
A: I checked with a colleague who wonders if the bishop is referring to an Apostolic Decree that came out in October 1972 Cum de Nomine (see Not. 8 (1972) 347-349 or Documents on the Liturgy 1963-1979, no. 1970).
However, Fr. Edward McNamara argues that the third edition of the missal has overruled it. Scroll to the bottom here: https://www.ewtn.com/catholicism/library/which-ordinary-to-mention-at-mass-4595