[Cameltoe]

first you need to make a variable:

new GotMusicPlayer[MAX_PLAYERS];

and when player login:

check if player have music player if player has the player then set GotMusicPlayer[playerid] = 1;

and when you play the cd player check if player has cd player with:

if (GotMusicPlayer == 1){
Doshit
}

hope you understand.