The suggestion readily brings to mind the "third orders" which allow lay people to share in the charism of a traditionally constituted religious order. Of these, the Franciscan third order - now known as the Secular Franciscan Order - is prominent and popular. The Constitutions and Rule of Life of the Secular Franciscan Order can be found at this web page, and fraternities of the Secular Franciscan Order exist in most parts of Britain. Another well known third order is that associated with the Order of St Benedict, whose members are known as oblates. Pluscarden Abbey, for example, has a community of oblates and its website explains the vocation of Benedictine oblates and includes the statutes for the oblates of its own monastery. A last third order worth mentioning is that associated with the Discalced Carmelite Order, the UK website of which can be found here and whose constitutions are posted here.
There are some common features that can be discerned in these third orders (do read the links above to fully understand the summary below, as each religious family is different):
the lay faithful are seen as fully a part of a religious "family" that includes consecrated men and women
the lay faithful undertake a time of formation in the life of their religious family that, while being shorter than that required for the consecrated life as such, precedes a commitment to the order
the manner of life of the lay faithful is modelled on the specific charism of the religious family to which they are associated
the lay faithful make a form of commitment to the life of the religious family that is mitigated to their circumstances as lay people; as with the commitment to the consecrated life, this is a public commitment that is received by the responsible superiors of the relevant instituteIn so far as the experience of life as a member of a "third order" involves a form of commitment, and in so far as that commitment has a specificity in ordering the life of the person making it to a particular way of living a Christian existence, it has the character of consecration as discussed in this earlier post in the present series. It can be understood as the specification of an original baptismal/confirmational consecration. However, it is not a commitment to a life of the evangelical counsels, and so does not involve a consecrated life in that fuller and more excellent sense.
The contribution that "third orders" continue to make to the life of the Church and to the Christian life of their religious families is somewhat hidden from view. I would not wish to be seen as underestimating that value in the cases of any of the three examples that I have cited. However, it is worth noting that revised constitutions in the cases of the Discalced Carmelites and the Franciscans suggest a greater secularity of the "third order" in relation to the first and second orders of their religious families than might have been the case in the past. Article 2 of the OCDS constitutions, for example, includes the slightly odd statement:
In light of the Church’s new theology of the laity, Seculars live this membership with a clear secular identity.
The underlying question appears to me less one about a theology of the laity and more one as to how society as a whole - which at the time of the founding of the Carmelite reform will have had a profoundly religious fabric that it does not have today - has changed. This might well demand a development in the way of life of the "third order" in favour of a certain "secularity" (the demands of living in a largely irreligious society, for example, might require a rather different adaptation of the charism to daily living now than it did in the past). This, however, is not to be equated with a "secularisation" of the charism of the religious family, that is, with a reduction of its essential character as a religious vocation to become instead the character of a lay vocation. While the language of "Secular Order" rather than "Third Order" must be seen as quite neutral in this regard, should the Secular Order come to carry the greater weight of the living of the charism of the religious family when compared to the members consecrated by vows of the evangelical counsels, perhaps in numerical terms or in apostolic activity, then the charism does risk suffering such a secularisation.