a kind of {HEAD ~ package selecting means} of selectively specifying {TAIL ~ the kind} of packages to be packaged 
of selectively specifying
a kind of { HEAD ~ package selecting means } of selectively specifying { TAIL ~ the kind } of packages to be packaged
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH