each container electronics and {HEAD ~ the first box control electronics} are housed within {TAIL ~ the first temperature side} of the first freezer 
are housed within
each container electronics and { HEAD ~ the first box control electronics } are housed within { TAIL ~ the first temperature side } of the first freezer
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH