\version "2.19.83"

semitone = {
  % How can I obtain a V-shaped bracket?
  \once \override Voice.HorizontalBracket.bracket-flare = #'(3 . 3)
}

tone = {
  \once \override Voice.HorizontalBracket.bracket-flare = #'(0 . 0)
  \once \override Voice.HorizontalBracket.edge-height = #'(0.5 . 0.5)
}

\layout {
  \context {
    \Staff
    \remove "Time_signature_engraver"
    \remove "Collision_engraver"
  }
  \context {
    \Voice
    \consists "Horizontal_bracket_engraver"

    % Is there any better alternative to get the edges of the bracket
    % aligned to the center of the notes?
    \override HorizontalBracket.shorten-pair = #'(0.9 . 1)
  }
}

\score {
  \new Staff \relative c' <<
    \cadenzaOn

    \new Voice {
      \voiceOne
      \tone
      c1\startGroup d\stopGroup
      \semitone
      e\startGroup f\stopGroup
      \tone
      g\startGroup a\stopGroup
      \semitone
      b\startGroup c\stopGroup
    }

    \new Voice \with {
      \override HorizontalBracket.direction = #UP
    } {
      \voiceTwo
      \hideNotes
      c1
      \tone
      d\startGroup e\stopGroup
      \tone
      f\startGroup g\stopGroup
      \tone
      a\startGroup b\stopGroup
      c
    }
  >>
}