From the 1974 Aposolic Exhortation “Marilias Cultus” at
vatican.va/holy_father/paul_vi/apost_exhortations/documents/hf_p-vi_exh_19740202_marialis-cultus_en.html :
“31. … Secondly there are those who, without wholesome liturgical and pastoral criteria, mix practices of piety and liturgical acts in hybrid celebrations. It sometimes happens that novenas or similar practices of piety are inserted into the very celebration of the Eucharistic Sacrifice. This creates the danger that the Lord’s Memorial Rite, instead of being the culmination of the meeting of the Christian community, becomes the occasion, as it were, for devotional practices. For those who act in this way we wish to recall the rule laid down by the Council prescribing that exercises of piety should be harmonized with the liturgy not merged into it.”
Also at the end of n. 48: “In fact, meditation on the mysteries of the Rosary, by familiaring the hearts and minds of the faithful with the mysteries of Christ, can be an excellent preparation for the creation of those same mysteries in the liturgical action and an also become a continuing echo thereof. However, it is a mistake to recite the Rosary during the celebration of the liturgy, though unfortunately this practice still persists here and there.”
The Rosary is recited in the liturgical ceremony “Order for the Blessing of Rosaries”. This is not a Mass. After the prayer of blessing, the rubric is: “1480 The recittion of the rosary follows, in the manner customary in the place.” Afer the rosary, there is a Concluding Rite to the ceremony. (Book of Blessings, Liturgical Press, Minnesota, 1989, ISBN 0-8146-1875-8, page 557.)
For the Benediction ceremony, involving Eucharistic Adoration, the rosary is given a unique place. From the 2002 Directory of Popular Piety and the Liturgy at
vatican.va/roman_curia/congregations/ccdds/documents/rc_con_ccdds_doc_20020513_vers-direttorio_en.html :
“The faithful should be encouraged to read the Scriptures during these periods of adoration, since they afford an unrivalled source of prayer. Suitable hymns and canticles based on those of the Liturgy of the Hours and the liturgical seasons could also be encouraged, as well as periods of silent prayer and reflection. Gradually, the faithful should be encouraged not to do other devotional exercises during exposition of the Blessed Sacrament (footnote 180: Cf. Reply ad dubium on n. 62 of the Instruction Eucharisticum mysterium, in Notitiae 34 (1998) 133-134; concerning the Rosary, see the following note.). Given the close relationship between Christ and Our Lady, the rosary can always be of assistance in giving prayer a Christological orientation, since it contains meditation of the Incarnation and the Redemption (footnote 181: Cf. PAUL VI, Apostolic Exhortation Marialis cultus, 46; Letter of the Congregation for Divine Worship and the Discipline pf the Sacraments (15.1.1997), in Notitiae 34 (1998) 506-510; see also the rescript of the Apostolic Penitentiary of 8 March 1996, in Notitiae 34 (1998) 511.).”