group vs brigade

group and brigade both are nouns.

Word	Noun	Adjective	Verb	Adverb
group	Yes	No	Yes	No
brigade	Yes	No	Yes	No

As verbs, brigade is a hyponym of group; that is, brigade is a word with a more specific, narrower meaning than group:

Other hyponyms of group include team, team up, embed, gang, gang up, pool.

group (noun)	brigade (noun)
any number of entities (members) considered as a unit	army unit smaller than a division, typically consisting of a small number of battalions
a set that is closed, associative, has an identity element and every element has an inverse
(chemistry) two or more atoms bound together as a single unit and forming part of a molecule

group (verb)	brigade (verb)
arrange into a group or groups	form or unite into a brigade
form a group or group together