Playlist Support - PowerPoint now can playback media from industry
standard playlist formats like ASX, WMX, M3U, WVX and WAX.
In PowerPoint (on the slide you want to begin playing the sounds),
choose Insert | Movies and Sounds | Sound from File...
Navigate to folder contain the playlist (*.wpl, *.m3u or another
format) file (you will probably have to change the "files of
type" option to "All files (*.*)"