In {TAIL ~ one embodiment}, {HEAD ~ an identifier} may be unique within the instant messaging group 
In
In { TAIL ~ one embodiment } , { HEAD ~ an identifier } may be unique within the instant messaging group
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH