Usage patterns
〈人〉がグループを作るfor people to form a group
The students in the class formed groups of four.
〈人〉がグループに入るfor someone to join a group
He joined the newly formed group.
〈人〉をグループに分けるto divide people into groups
The teacher divided the students into five groups.
グループで〈動詞〉to do something as a group
We discussed it as a group.