[TwinkiDaBoss]

Its quite a small problem, but the chat is shown to everyone

PHP код:

SendFactionMessage(playerid,string[]) {
    foreach(new i : Player) {
        if(AccInfo[playerid][PlayerFaction] == AccInfo[i][PlayerFaction]) {
            Msg(i, COLOR_LIGHTBLUE, string);
        }
    }
    return true;
} 


[Ritzy2K]

Change playerid with 'i'.
Edit: Patrick beat me to it.

[DRIFT_HUNTER]

That function is completely ok. You probably using it inside OnPlayerText
When you send that message return 0 so that message that player typed is not sent (you are sending it with Msg function)