I don't know of any way to identify them after opening in numbers, however, If you can get an export from excel of the formulas used, you could then compare to the functions list for numbers posted here. anything missing is your group you are looking for.
to get the formulas you can either
a) write a vba script to go through all populated cells and pull them out to a text file (if there are lots of them)
b) Type Ctrl ~ to see formulas, then copy them out to a text editor (If not too many)
edit: I just made a new tip (screwed up the title should be excel v numbers, not numbers v numbers )based on this as i couldn't find a list of "missing formulas", and i have seen this kind of question many times before. I dont know if this is a permanent link , or where the tips show up, but here is the one i got after creating it today:
https://discussions.apple.com/docs/DOC-250000546
Jason