Rekeying pattern for duplex with shared front door

Question

I have Kwikset KW-1 5pin locks (At least 10 of them). Since I have a duplex, I'd like to make two keys and have three locks (Unit 1, Unit 2, and Common)

So that each tenant can have a single key which opens the front/rear/garage door and their unit, but not the other unit.

Is this possible? What would the pin patterns need to look like?

Edit:

I want each tenant to hold a single key (they currently carry two). That key should open the front door (which is shared) and their unit which has no exterior door.

Which to me says there should be two patterns for keys (each unit)

And three patterns for locks:

• Shared, that can be opened by either key
• Unit 1, that can only be opened by key 1
• Unit 2, that can only be opened by key 2

Second Edit

Been reading a bit about master pins. Maybe the right answer is put the same change key on the front door and unit one, and just use the master myself. Then I can open all doors with one key, and they can open just common and unit one. Obviously that won't work in a few years when we move on and rent both out though.

Answer 1

See if your particular lock shows up here:

http://www.imlss.com/images/pdf/kwikset_Rekeying_Manual.pdf

Though I think if you have a competent locksmith, you just tell her/him what you want, and it happens, you don't have to tell them how to do their job. And you have an incompetent one, telling them how to do their job is not likely to help, either. So anything past this is merely for information, unless you are planning to try and do this yourself, which can be complicated for boring legal reasons in many LAHJ's rather than technical ones.

I'm not a locksmith (I think we have a few posters that are) but with 5 pins that can be set 6 ways (each) you have many, many key combinations available, and you need, at most, 4 that work together, in 3 lock types.

In some sense you're delving into "sub-master" to get what you want, with each key working specific things - so the unit keys operate the common lock

52463 Let's say that's the common door.

Now, if you put a master pin of size 2 in position 1 and 4 of the common locks (with bottom pins of size 3 and 4) You can have Unit 1's lock set to 32463 and unit 2's lock set to 52443 and you get what you asked for, with neither being able to open the other via filing down a key.

If you want a full-on master or a front door only key, it's more of the same. Actually I guess I gave you a front-door only key while trying to avoid the "file down to open the neighbor" condition from the comments. If you are hiring a locksmith, they should be able to work out the details without your input on the specifics of the pins used. As such I'm going to stop here for now.