Would this work?
package music
{
function clientCmdChatMessage(%a,%b,%c,%fmsg,%cp,%name,%cs,%msg)
{
parent::clientCmdChatMessage(%a,%b,%c,%fmsg,%cp,%name,%cs,%msg);
if(%msg $= "playtest")
{
alxPlay(musicData_After_School_Special.ogg);
}
}
};
activatepackage(music);