How to control sound separately in flash?

some times, we stop a music, another sound will be off.  how to control the sounds separately?

this is way:

createEmptyMovieClip(”sound_1″, 1);
my_sound_1 = new Sound(sound_1,1);
my_sound_1.attachSound(”music_xxx”);
my_sound_1.start();

createEmptyMovieClip(”sound_2″, 2);
my_sound_2 = new Sound(sound_2,1);
my_sound_2.attachSound(”music_xxx”);
my_sound_2.start();

Note: the 2 MovieClips need be placed in different layer. for example:one is in 1 layer, another is in 2 layer.

now when we control my_sound_1, can not affect my_sound_2.

Thanks WenJie for his advice!

XueYong