Yes, it is a common occurrence, but… No, there is no provision for it. Some practices just sort of spring up and start happening so regularly that people just assume they are legitimate.
When this sort of thing happens, I would expect the proper course of action would be for the pastor to ask the bishop if the practice is permissible. The bishop can render a ruling if the matter is within his competency (his realm of authority), but otherwise, he should bring the matter to the Congregation for Divine Worship and the Discipline of the Sacraments, and let
them render a ruling (and provide guidelines if necessary).
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Art. 62 — The Congregation for Divine Worship and the Discipline of the Sacraments does
whatever pertains to the Apostolic See concerning the regulation and promotion of the sacred liturgy, primarily of the sacraments, without prejudice to the competence of the Congregation for the Doctrine of the Faith.
Art. 63 — It fosters and safeguards the regulation of the administration of the
sacraments, especially regarding their
valid and licit celebration. It grants favours and dispensations not contained in the faculties of diocesan bishops in this matter.
Art. 66 — The Congregation provides
attentive supervision to ensure that liturgical norms are accurately observed, and that
abuses are avoided and eliminated where they are found to exist.
Art. 70 — The Congregation gives
assistance to bishops so that, in addition to liturgical worship, the prayers and pious exercises of the Christian people, in full harmony with the norms of the Church, may be fostered and held in high esteem.
Not every liturgical decision is within the faculties of the diocesan bishop or even the Conference of Bishops. GIRM 386-399 lists adaptations that are up to the bishop or Conference; if that list is exhaustive (or at least indicative of the whole), then I don’t think adding blessings to the Rite of Communion is within their purview.
Bishops (and Bishops’ Conferences) should have no fear or reluctance to contact the CDWDS on such matters. It will prevent most liturgical errors and abuses.