high society vs elite group

high society and elite group both are nouns.

Word	Noun	Adjective	Verb	Adverb
high society	Yes	No	No	No
elite group	Yes	No	No	No

As nouns, elite group is a hypernym of high society; that is, elite group is a word with a broader meaning than high society:

high society: the fashionable elite
elite group: a group or class of persons enjoying superior intellectual or social or economic status

Other hypernyms of high society include elite.

high society (noun)	elite group (noun)
the fashionable elite	a group or class of persons enjoying superior intellectual or social or economic status