18 Special concern should be shown for those among the faithful who, on account of their way of life, cannot sufficiently make use of the common and ordinary pastoral care of parish priests or are quite cut off from it. Among this group are the majority of migrants, exiles and refugees, seafarers, air-travelers, gypsies, and others of this kind. Suitable pastoral methods should also be promoted to sustain the spiritual life of those who go to other lands for a time for the sake of recreation. Episcopal conferences, especially national ones, should pay special attention to the very pressing problems concerning the above-mentioned groups. Through voluntary agreement and united efforts, they should look to and promote their spiritual care by means of suitable methods and institutions. They should also bear in mind the special rules either already laid down or to be laid down by the Apostolic See which can be wisely adapted to the circumstances of time, place, and persons.
Source: Christus Dominus (Vatican.va)