Each zone may store instant messaging information for a subset of the peers at locations in the zone indicated by hashes of identifiers of {HEAD ~ the peers} in {TAIL ~ the instant messaging group} 
in
Each zone may store instant messaging information for a subset of the peers at locations in the zone indicated by hashes of identifiers of { HEAD ~ the peers } in { TAIL ~ the instant messaging group }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL