How to separate these voices??

[steve]

  Howdy!

         How do I get the bass quarter notes to separate from
 the middle 8ths? They are fused as 8ths, and

\override NoteColumn.force-hshift = #1

     shifts both the middle and bass voices?


\version "2.18.0"

 voiceone = \relative c' {
    <<
    { e2. | }
      \\
    { gis,8[ b] gis[ b] gis[ b] | }
    >>
 }

 voicetwo = \relative c {
    < e, e' >4 dis' cis |
 }


guitar = << \voiceone \\ \voicetwo >>


             thanx - steve