groupist
/ˈɡruːpɪst/noun
1A member or adherent of a group.
2With capital initial. A member of the Oxford Group Movement. Compare Grouper. Now historical.
adjective
1With capital initial. Of or relating to the Oxford Group Movement. Now historical.
2Characterized by the desire or tendency to belong to a group; (also) that tends to view people as members of a group, rather than as individuals.
Origin
Mid 19th century (in an earlier sense). From group + -ist.