[Extremo]

Use two arrays, one holds the keys, one is a boolean like this:

pawn Код:

enum HouseInfo /* or whatever u haz */
{
    bool:KeyEnable[MAX_KEYS],
    Keys[MAX_KEYS]
};

/* then in your command u check if KeyEnable[KEYID] and if it is, you allow him to have a key on that array
    and in order for you to check if he still has keys left u just loop through MAX_KEYS and check if theres one
    which is KeyEnable but Keys is not set yet. Simple.
*/