This field uniquely identifies the group within the scope of the given Fabric.
This field references the set of group keys that generate operational group keys for use with this group, as specified in Section 4.16.3.5.1, “Group Key Set ID”.
A GroupKeyMapStruct shall NOT accept GroupKeySetID of 0, which is reserved for the IPK.
See
MatterSpecification.v13.Core § 11.2.5.3