Without being forced to use fantasy, I can easily remember of group exams at school where each year I was instructed to undress in white briefs with a group of 15 or more classmates in a locker room adjoining the exam room where we entered one by one. It was in the 60's and it was not specific to our school, it was the common set up for all examinations of boys at school or for sport, from elementary school until last grade of high school at 17-18 age ( even naked before entering in the exam room at high school under instruction of a mean Pe teacher, a former military man who had decided that to win time each boy who was the next to be examined might remove his underwear and stand naked in plain view of all others and him along the wall near the door of the exam room before he was called to enter and that means that all the exam was performed in the nude, even eyes test, or urine test, weigh-in and so on .. in front of the female doctor, the female nurse and two years about three a young nursing student. But the examination was performed one by one student in the exam room.
It was the same at university or superior school with undressing in group before an examination alone, no line of students for the examination, but I have read on one forum that in the last 70's /beginning of 80's at the university of Montpellier, there was during several years group physical examinations of boys students without any privacy with a line of students in briefs and examined by a medical staff ( male doctor and female nurse ) without intimacy in plain view of all the line which meaned that they might remove under instruction of the male doctor their briefs to let the doctor inspect their genitals and it was written that it lasted a long time before they could put their brief again as if the male doctor was a little sadistic and pleased to expose a guy naked to others, and there was without any privacy the awkward “turn around, bend over and spread your cheeks ” . I don't know if it was true but anyway some students complained about that set up on a forum and said that after a few years there was a change towards more respect of privacy. For me it was just like at school, undressing in group in briefs with other male students.
But of course for me the idea of group exams is linked to my own physical examinations for military service, they were real group exams with nudity for one or two hours in a large group and no privacy at all, even for peeing and exposure not only in front of medical staff - fortunately all male for me- but also non commissionner officers in a pre-induction center ( three times for me) and after at induction.
And the most vivid memory of draft physical exams is my report in front of the draft commission board when I reached 18 agen with a physical examination stark naked for a large group of draftee all same age in line supervised by a few non commissionners officers before being examined one by one but in plain view by a military doctor in front of twelve men ( fortunately for me there was no woman among the commission board) sitted behind a large desk who were representatives of local authories - the town and so on end national authorities in civil clothes and suprerior officers in military uniforms- all non medical persons- it was very impressive, it lasted about ten minutes by draftee and each might walk naked in front of the members of the commission board, stand like at attention front and back, bend over and touch ankles under instruction of the doctor but mre embarrassing under all their eyes and so on.
it took time in a morning and it was an event that you remember all your life.