\version "2.19.16"

#(define adjust-for-note-head
  (lambda (grob)
    (let* ((refp (ly:grob-system grob))
           (bar-coord (ly:grob-relative-coordinate grob refp X))
           (all (ly:grob-array->list (ly:grob-object refp 'all-elements)))
           (note-heads
             (filter
               (lambda (n)
                 (eq? (assq-ref (ly:grob-property n 'meta) 'name)
                      'NoteColumn))
               all))
           (note-head-coords
             (map
               (lambda (heads)
                 (interval-center (ly:grob-extent heads refp X)))
               note-heads))
           (coords-to-right
             (filter
               (lambda (coord) (< bar-coord coord))
               note-head-coords))
           (closest-coord
             (if (pair? coords-to-right)
                 (apply min
                       (map (lambda (coord) (- coord bar-coord))
                            coords-to-right))
                 0)))
          
      (set! (ly:grob-property grob 'extra-offset) (cons closest-coord 0)))))
      
centerBarToNote = \override Staff.BarLine.after-line-breaking = #adjust-for-note-head   
centerSpanBarToNote = \override StaffGroup.SpanBar.after-line-breaking = #adjust-for-note-head

{ 
  \new StaffGroup <<
  \centerSpanBarToNote
  \time 2/4
    \new Staff {
      \centerBarToNote
      \override Stem.stencil = #point-stencil
      \repeat unfold 30 { d' d' }
    }
    \new Staff {
      \override Stem.stencil = #point-stencil
      \centerBarToNote
      \repeat unfold 30 { d' d' }
    }
  >>
}

\layout {
  \context {
    \Score
    \override SpacingSpanner.strict-note-spacing = ##t
    proportionalNotationDuration = #(ly:make-moment 1/8)
  }
  \context {
    \Staff
    \remove "Time_signature_engraver"
    %\override BarLine.transparent = ##t
  }
}