new [IR]; // The name of your gang

[IR] = AddStaticVehicle(451,1890.1632,1989.1708,13.4920,179.9223,6,6); // This will spawn a turismo in the parking lot in LV

public OnPlayerStateChange(playerid, newstate, oldstate) // The OnPlayerStateChange function
{
  new GangName[24]; // We create a variable which will contain the gang name.
  GetPlayerName(playerid, GangName, sizeof(GangName)); // We use GetPlayerName to store the name in 'GangName'.

  if(newstate == PLAYER_STATE_DRIVER) // Check the new state, since he's the driver in this case, we continue.
  {
   new Vehicle = GetPlayerVehicleID(playerid); // This saves the player's vehicle id into the variable 'vehicle'
   if(Vehicle == [IR]) // We check if the vehicle is the one we don't want everyone to enter
   { // It is, so we continue.
     if(strcmp(GangName,"[IR]",true)) // We use strcmp to check if the player who entered the car is the same as '[IR]'
     { 
      RemovePlayerFromVehicle(playerid); // It's not, so we remove the player from the car.
      SendClientMessage(playerid, 0x33AA33AA, "This car been belongs to [IR] "); // And we inform him about why he got removed from the car.
     }
   }
  } 
  return 1;
}

#define MAX_GANGS 2

#define GANG_IR 0

#define GANG_GS 1

#define MAX_GANG_VEHICLES 10

new GangCars[MAX_GANGS][MAX_GANG_VEHICLES];
public OnGameModeInit()
{
  GangCars[GANG_IR][0]=AddStaticVehicle(522,0,0,0,0,-1,-1);//IR, gang vehicles can go up 9 (because MAX_GANG_VEHICLES is 10)
  GangCars[GANG_IR][1]=AddStaticVehicle(522,0,0,0,0,-1,-1);
  GangCars[GANG_IR][2]=AddStaticVehicle(522,0,0,0,0,-1,-1);
  GangCars[GANG_GS][0]=AddStaticVehicle(522,0,0,0,0,-1,-1);
  GangCars[GANG_GS][1]=AddStaticVehicle(522,0,0,0,0,-1,-1);
  GangCars[GANG_GS][2]=AddStaticVehicle(522,0,0,0,0,-1,-1);
  return 1;
}
public OnPlayerStateChange(playerid,newstate,oldstate)
{
  if(newstate==PLAYER_STATE_DRIVER)
  {
    new pname[24];
    GetPlayerName(playerid,pname,sizeof(pname));
    for(new gangcar;gangcar<MAX_GANG_VEHICLES;gangcar++)
    {
      if(GetPlayerVehicleID(playerid)==GangCars[GANG_IR][gangcar])
      {
        if(strfind(pname,"[IR]")==-1)RemovePlayerFromVehicle(playerid);
      }
    }
    for(new gangcar;gangcar<MAX_GANG_VEHICLES;gangcar++)
    {
      if(GetPlayerVehicleID(playerid)==GangCars[GANG_GS][gangcar])
      {
        if(strfind(pname,"[GS]")==-1)RemovePlayerFromVehicle(playerid);
      }
    }
  }
  return 1;
}