a reservoir connected in common to {HEAD ~ said flow systems} to receive {TAIL ~ a flow} of fluid from each said system 
a reservoir connected in common to { HEAD ~ said flow systems } to receive { TAIL ~ a flow } of fluid from each said system
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH