Forcing line breaks without changing bar lines

[Li Jie Wong]

Is it possible to make a function that will do the equivalent of...

  \break

when at a bar boundary, and

  \bar "" \break

otherwise?

Basically, I just want a line break at a point, without lilypond fussing about whether the break is at a valid position or not, but I also don't want to erase any bar lines (which happens if I just indiscriminately use \bar "" \break).

Thanks,

lj