The set of IV Zone members that form this IV zone.
The IV zone members are identified by
civrZoneMemberIndex object in the civrZoneMemberTable.
If a particular bit has a value of '1', then the
corresponding zone member is a part of this zone.
All other zone members have '0' in their
positions or not present in the string.
This object is read-only; changes to its value
are made by the agent as and when associated
entries are created/deleted in the
civrZoneMemberTable.
The default value is the zero length string.