You don't need a script for that, you can use the Quick Text feature for something like that. That is exactly what they are there for
eg:
QuickText:
/sound #id_of_the_sound
/sound #id_of_the_sound
/sound #id_of_the_sound
Alias of QuickText:
/multisound
PS: note that there can only be one sound playing at a time though.