Daily Mass is arranged by the operator with each sacristy. At St. Peter's Basilica a visiting priest presents a celebret, the letter of good standing from his bishop or superior, and group Masses are scheduled early in the morning at side altars or in the grottoes. Lourdes, Fatima, and Assisi have booking offices for group Masses and expect requests weeks ahead.

The chaplain does not replace the guide and is not the organizer. Confirm in writing who the priest is, whether his place is complimentary, and who covers his costs if enrollment falls short of the threshold.