how to play multiple ogg in same time?

[Zip]

hello ppl!
im working at my last game earth invasion (space invader remake)
i have a problem i use ogg file for SFX
but when alien shot and my tank shot ogg cant be in same time, 1 Play_song cover other playsong, i can resolve that problem?
if i will use wave i can solve?

[Zip]

solved, using wav for sfx and ogg for music background