Automatic beams

[Helge Kruse]

Hello,

I need to typeset a piece but want to keep the original beaming. The 
beams that Lilypond uses per default does not match. I know I can add 
the [] to manually control beaming, but I hope I can do this more 
declarative as described in notation reference "1.2.4 Beams".

In this measure I want to break up the sextuplets in treble to a 3+3 
group. The semiquavers should be grouped 2+2.
The quavers in the base staff should be grouped 2+2.

\version "2.14.2"
\new PianoStaff <<
  \new Staff {
    \time 4/4 \key g \major
    \set Timing.baseMoment = #(ly:make-moment 1 16)
    \set Timing.beatStructure = #'(2 2 2 2)
    \relative c'' {
      \times 4/6{c'16 a b c b a } \times 4/6{r e fis g fis e }
      fis16 d fis a r fis a c | % 24
    }
   }
  \new Staff {
    \time 4/4 \key g \major \clef bass
    \set Timing.baseMoment = #(ly:make-moment 1 8)
    \set Timing.beatStructure = #'(2 2 2 2)
    \relative c {
      fis8 d' g, d' a d b d | % 24
    }
  }
>>


I can change the beaming with beatStructure, but baseMomemt doesn't 
change anything. I also tried with Staff and Voice context but got the 
same result.

How can I achieve the described grouping?

Regards,
Helge