Sacerdotalis Caelibatus §80

⁸⁰ So the unity of spirit among priests should be active in their prayers, friendship and help of all kinds for one another. Ore cannot sufficiently recommend to priests a life lived in common and directed entirely toward their sacred ministry; the practice of having frequent meetings with a fraternal exchange of ideas, counsel and experience with their brother priests; the movement to form associations which encourage priestly holiness.