The superior makes the assignment after responding to the request of a bishop. That’s the way it works for religious and for societies. What is happening with many societies is that they are replacing the religious, because religious are returning to their particular work and to life in community. With religious leaving these slots open, societies like the FSSP, Maryknoll, Vincentians, etc, are being invited to fill them. It’s up to the superior to take the slot or not.
What can happen with a society is that it may have one or two priests more than it can place in parishes. The society has to find a place to assign them.
To the man in the pew this may be simple. The parish is big and can use three priests. To the superior of the society, it’s not so simple. The parish is big, but it will only pay for two salaries. The superior has no control over the budget of the parish or the regulations of the diocese. He accepts the parish as is.
These men may belong to the FSSP, Vincentians, Maryknoll or some other society, but they remain secular men. They must be paid a salary and benefits. Otherwise, how do they eat?
Religious don’t have to worry about this, because they don’t get paid. Everyone shares whatever comes in. They can place 20 in a parish made for three. The bishop does not care as long as they do not draw 20 salaries from the parish collection, because that would drain the parish. I know one religious house that’s attached to a parish that has 45 men and parish pays for three. The rest of the income comes from other sources.
That’s how you can end up with a society priest in an apostolate that is outside of their usual. There is a vacancy and there is a man who needs a job. It’s a perfect match. The superior takes it. Once he accepts it, the man is subject to the lawful authorities of the agency. That’s part of the agreement. Superiors and dioceses work these things out, but the laity is not informed of the details. They have no need to know. We all know what they say about too many cooks in the kitchen.
Fraternally,
Br. JR, OSF