Colouring analysis brackets

[Édouard Gilbert]

Hi,

I'm not using Lilypond for a long time, so sorry if my question seems 
ridiculous.

I'm wondering if there is a way to print horizontal brackets in different 
colours
even when they start on the same note. Here come an example
(don't mind the notes or structure, they are nearly random).

%====================
    \header
  {
    title = "Title"
  }
  \score
  {
    {
        \once \override Staff.HorizontalBracket #'color = #red
        d'\startGroup\startGroup\startGroup\startGroup\startGroup
        d'\stopGroup ees'\startGroup e'\stopGroup\stopGroup e'\stopGroup
        e'\stopGroup c'\startGroup\startGroup c'\startGroup\startGroup
        c'\startGroup cis'\startGroup c'\stopGroup\stopGroup\stopGroup
        c'\stopGroup\stopGroup g\startGroup a\startGroup
        bes\stopGroup\stopGroup\stopGroup\stopGroup
   }
    \layout
    {
      \context
      {
        \Staff \consists "Horizontal_bracket_engraver"
      }
    }
  }

\version "2.8.5"
%====================

As one can see, the five brackets opening on the first note are printed in red.
Is it possible to print, say, the second on in red, the fourth one in blue
and the others in black?

Thanks for your help,

Édouard