stock AdmChat(mess[])
{
        for(new i; i < MAX_PLAYERS; i++)
        {
                if(Player [i][pAdmin]> 1) SCM(i, -1, mess); // замените на вашу.
        }
        return 1;
}

CMD:a(playerid, params[])
{
              new string[128],sendername[MAX_PLAYER_NAME];
              GetPlayerName(playerid,sendername,sizeof(sendername));
              format(string,COLOR_RED,"[ADMIN_CHAT] {14FE04}%s[id:%d]: {CCFE04}%s ",sendername,playerid,params[0]);
              AdmChat(string);
      return 1;
}