[Vrondakis]

You do it in the same way. If you want all the "workers" to be allowed to get in the hydra + tank + truck, you do the exact same thing.

pawn Code:

new workers[MAX_PLAYERS][playerid] = // The list of skin ids that are allowed.
{
    27,
    38,
    29,
    213,
    219,
    6
    };

new vehicles[MAX_PLAYERS][playerid] = // The list of vehicles that the workers are allowed to get into.
{
    520,
    528,
    532,
    };


    if( oldstate == PLAYER_STATE_ONFOOT && newstate == PLAYER_STATE_DRIVER )
    {
    //If they got into a car from being on foot.
        if( GetVehicleModel(GetPlayerVehicleID( playerid )) == vehicles)  //naudoti || masina ||
        {
            if( GetPlayerSkin(playerid) != workers) //naudoti || skinas ||

            {
                //If their skin is not 27
                //Remove them and send message.
                RemovePlayerFromVehicle( playerid );
                SendClientMessage( playerid,0xFF000000, "Noredami vairuoti si transporta turite buti elektriku" );//-1
                return 1;
            }
            else
            {
                SendClientMessage(playerid, 0xFF000000, "Atsisedote i transporta. Jeigu dirbate, tada dirbkite savo darba");
                return 1;
            }
        }
    }
    return 1;
}

Should work, not tested