Have you ever heard of a security door like this?

There are such doors, but it's not like you can only use one of the six keys you said.

What I have done is that two sets of keys, one is two, which is used when looking at the house (can also be used during decoration) and the other set is six, which is used when you move in, when you use the latter set (that is, the set of six), the front set is not easy to use (that is, the set of two).

The current security doors are like this.

There are two sets of keys A and B, and A keys are used for decoration, usually 2 or 3. After the renovation is completed, after the B key (usually 6) is activated, one of the lock cylinders in the door lock is opened, and the A key is invalid, which means that the A key cannot open the door.

The two sets of keys A and B differ only on the top one tooth.

With such locks, the key is magnetic, and since the magnetic distribution inside the key is not the same, just like the password.