I'm having a little buffet at work to celebrate going on mat leave, and I'm not really sure how much food to buy. I work in a hospital so all colleagues work quite closely together. There will be about 40 members of staff on duty and around 8 have put their name down for the buffet and will be contributing towards it.. These are mainly my close colleagues. I do get on with everyone though! I'm obviously bringing sweet things for everyone to enjoy but I'm also thinking of bringing a few savoury bits as well, but not sure on the etiquette for the buffet in general? I am expecting staff who aren't contributing to help themselves as well which may make it awkward if the people who are contributing have a late lunch and don't get much (or any) food! But equally I don't want it to just be to take something if you've contributed.. How do I handle this fairly? Thanks
Edited to add for context, it's a shared staff room which everyone eats in at different times depending when they get a break, but there's usually 8-10 people on their lunch at the same time