Since Twelve-Step programs are anonymous, the rental from those groups came to St Mary of the Angels in cash, mostly ones. Other groups using the hall paid by check on the accounts of the groups.
I'm assuming that Ordinariate groups in formation must incorporate at some early stage in their development, and certainly must exist as formal entities to be recognized at all by the Ordinary. A visitor now tells me that Houston "will soon have a state-of-the-art parish accounting software system which will be mandatory for every group to use. This package, which will cost around $450 per group per year, is used by many Catholic dioceses (like Detroit) but seems a bit elaborate for OCSP, which has many groups with membership in the low double digits. Houston is picking up the cost for the first year."
The visitor suggests that some groups may need to set up bank accounts and so forth for the first time in order to accommodate this, but I'm simply not sure if this hasn't already been done. It does, though, lead to the question of what the typical plate-and-pledge amounts to for the smaller groups, and what their expenses are. If a smaller group has 15 pledging entities each contributing $20 per week, that's $300, but I'm not sure how realistic that is -- as an usher at my Catholic parish, I see many people putting much smaller amounts in the basket (and plenty just pass it by), and our pastor has asked those pledging less than $5 per week to increase the amount to $5.
On the other hand, I don't know what hall rental amounts to, either, nor what other expenses a small group has, assuming the clergy is non-stipendiary. This is information I badly wanted to know when I was briefly treasurer of St Mary's -- these were the sorts of things that nobody in the Diocese of Ft Worth in-group seemed much concerned about, and nobody was providing any sort of guidance. It seems to me that some uniform system of accounting must be essential to the Ordinariate -- but frankly, it raises the question of how many smaller groups can, or should, continue.