Polymultiple

undefined: Polymultiple systems have a large amount of partitionary members, typically over 100.

The "multiple" used here does not refer to the large plural umbrella but to the specific experience of having distinct headmates, as compared to median & OSDD-1a systems.

Related Terms
Polyplural refers to any large system, whether they are partitionary or not; in addition, polyfaceted & polyfragmented describe similar phenomena.

DID is a common example of a partitionary or multiple system.