Group appearing in Copenhagen usually (5)
I believe the answer is:
genus
'group' is the definition.
(genus is a kind of group)
'in copenhagen usually' is the wordplay.
'in' says the answer is hidden in the clue.
'GENUS' is hidden within 'copenhagen usually'.
'appearing' is the link.
(Other definitions for genus that I've seen before include "Class of animal" , "Taxonomic grouping" , "Category between family and species" , "Latin class?" , "Part of the family" .)