I have read some scripts recently which features a scene that refers to a group of background characters without naming them, but to distinguish between them uses "descriptive names" instead.
Eg. The Big Nurse kindly comes over with a blanket. The Pretty Nurse works on the EKG machine while the Trainee Nurse rushes in to help everyone.
What I like about this format is that it capitalizes the descriptive names as if they were actual names without affording the character a proper name (since they are overall insignificant to the story), indicates their relevance (they are all nurses) and provides the bare minimum description for us to distinguish them. I feel this works better than Nurse 1, Nurse 2 etc since it is easier to distinguish them this way, and also better than giving them actual names because that would distract the reader into thinking they are important yet we never see them again.
Not sure if it's just me, but I haven't ever seen this kind of naming format in book writing and I am wondering if it's ok practice to use it?