I was requested to write that [A/the clinic(s) that open(s) out of regular official hours of a hospital] as a noun phrase, supposedly a concise and natural-sounding one.
There are several issues for me to come up with the noun phrase.
Singular vs. plural: This is a clinic (or clinics?) run by a hospital (let's say the hospital's name is Springfield). I'm not sure if I should think of the clinic as a singular or plural noun. Physically, there are several such clinics located all over the hospital. However, I think it's possible to think of all of them collectively as a clinic.
Out of regular official hours sounds somewhat awkward to me. I thought of a few alternatives such as non-standard hours or non-regular hours, but I'm afraid that the terms might be non-standard, and they might not convey the intended meaning precisely.
The use of apostrophe s: Supposed that I could come up with such a noun phrase (I currently use An out-of-regular-official-hours clinic), can I use the [X's Y] pattern? Or it has to be [Y of X]?
- N1: Springfield's Out-of-Regular-Official-Hours Clinic
- N2: A Springfield's Out-of-Regular-Official-Hours Clinic
- N3: The Springfield's Out-of-Regular-Official-Hours Clinic
I think N1 might work, but both N2 and N3 are risky. The genitive case (Springfield's) seems not to get along with the articles (a/the) quite well.
How should I phrase it (the noun phrase)?