Controlling sound from other levels

(Almost there with my website, will stop asking questions after this one!)

I now have my sound clip working in a container swf (level0)…
Can I control this sound clip from other levels that have been loaded into level 1 from the container swf?
Would it be something like

_level0.mysound.setVolume(30);

If so, where do I name the music ‘mysound’? I have simply dragged the music into the main timeline. Would it be better if I loaded it externally?

Thanks!