Can’t stop people from grouping together:
23. (People) are by nature social, and consequently they have the right to meet together and to form associations with (others). They have the right to confer on such associations the type of organization which they consider best calculated to achieve their objectives. They have also the right to exercise their own initiative and act on their own responsibility within these associations for the attainment of the desired results(Cf. Leo XIII’s encyclical letter Rerum novarum, Acta Leonis XIII, XI, 1891, pp. 134-142; Pius XI’s encyclical letter Quadragesimo anno, AAS 23 (1931) 199-200; and Pius XII’s encyclical letter Sertum laetitiae, AAS 31 (1939) 635-644).
24. As We insisted in Our encyclical Mater et Magistra, the founding of a great many such intermediate groups or societies for the pursuit of aims which it is not within the competence of the individual to achieve efficiently, is a matter of great urgency. Such groups and societies must be considered absolutely essential for the safeguarding of (human) personal freedom and dignity, while leaving intact a sense of responsibility.( Cf. AAS 53 (1961) 430)
Seems straight-forward, right?