indicate where melody continues

[Simon Dahlbacka]

Hi,

I'm trying to create a sheet where there are at times two voices (but mostly one) on one staff and occasionally it is not obvious which one is the melody and which is the second voice, so I'd like to have some kind of indication where the melody continues, (like an arrow or "glissando"-ish line or something similar)

I have essentially the following

melody = \relative c' {
c d g b % let's say I want an indication here between d and g
}

second = \relative c' {
e f e f
}

and 

\score {
\context Staff = "full" <<
 \context Voice = "melody" {
<<
\melody
\second
>>
}
>>
}

I tried using a \glissando (and it would have been good enough if it only worked), but inevitably the line went from the d in the melody to the e in the second voice :( , and the same problem also with phrasing slurs.

Now, this is more or less the first song I'm typesetting so I'm a newbie, so hopefully there is something simple I've overlooked. In that case I'd appreciate a pointer to where to start to RTFM ;)

regards,

Simon