This is the first part
still first part ^Job This is the new part

#!/bin/ksh

typeset srcfile="file"
typeset -i cnt=1
typeset line=""

exec 3>${srcfile}.part${cnt}                # define our output file
cat $srcfile | while read line ; do
                                            # we have a line with a splitter
     if [ $(print - "$line" | grep -c "\^Job") -gt 0 ] ; then
          print -u3 "${line%%^Job*}"        # put the part of the line before
                                            # the splitter to the old output
          exec 3>&-                         # close output
          (( cnt += 1 ))
          exec 3>${srcfile}.part${cnt}      # open the next part
          print -u3 "${line##*^Job}"        # output part of line after the
                                            # occurence of the splitter
     else                                   # this is a regular line, just print
          print -u3 "$line"
     fi
done
exec 3>&-                                   # close last output file

exit 0