global =
{
     \key g \major
     \time 6/8
}

hautboisI =
{
     \relative c'''
     {
          \times 3/2 { a8 a } \times 3/2 { a a }
     }
}

hautboisII =
{
     \relative c''
     {
          \times 3/2 { f8 f } \times 3/2 { f f }
     }
}

\score
{
      \new Staff << \global \partcombine \hautboisI \hautboisII >>
}