yes,

just import your mp3 and select a single keyframe , go to property's , select your sound and then on the option "sync" set to loop

so:

import sound > select keyframe > open property's > select sound > set "sync" to 'loop';

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when moving away from the frame with the sound, use:

Code:
stopAllSounds()
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this is the simplest way to do it id imagine, however i don't know how buggy it will be.

i personally would use Actionscript to load the MP3 via a linkage in the library.

if you have any problems using this method. ill post an Actionscript method and example.

goodluck