accept first additional data received from the second data enterer into the system if the data is entered in a format compliant with {HEAD ~ a second set} of {TAIL ~ rules} 
of
accept first additional data received from the second data enterer into the system if the data is entered in a format compliant with { HEAD ~ a second set } of { TAIL ~ rules }
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 HEAD REL TAIL TAIL TAIL TAIL TAIL