Any locksmiths in the house?

I am considering adding limited locksmithing services to what we do. 

We frequently have customers ask for multiple keys for hardware we install. While keys aren't expensive, the time to go to a shop and have them cut is. Cutting them in-house would be fairly easy. With that in mind, I've ordered a key cutting machine and a decent assortment of key blanks for commercial locks. 

I'm pretty sure that with a pin kit and a handful of tools, I could rekey just about any lock or cylinder to an existing key without too much trouble. 

However, I also have a small  hospital that wants us to take care of all of their locksmithing as well. They want to buy hardware keyed to their system without having to deal with a separate locksmith. The one company local to them is apparently not very good. They have what I believe is a Sargent master setup and that's where I get out of my league. The facilities manager isn't sure what he has so he dumped a keyring on me to figure it out. While I think I understand how the system works, I would love some pointers toward good information. 

I have a list of handsets he wants to replace now and being able to key them in-house would be a real benefit. 

Normal disclaimer that I have no idea what I'm talking about, but I'd imagine the manufacturer would probably be able to help.  I'd chat up their sales drone and explain that you maintain the doors for a hospital, and what you're trying to do.  I'm imagining that there's a fairly good guide to re-keying, along with a pin kit they'd be happy to sell you.

In the manufacturing world, I've always been fairly impressed by how far I can get with 20 minutes on the phone for tech info. 

I have done master and grandmaster setups, but it was a long time ago... I remember making charts by hand to ensure you could not have a situation where a key accidentally gets you where you should not go.  Also more prone to jamming and a lot easier to pick, because there are multiple tumblers involved per location.

In reply to Toyman! :

I'm a locksmith for a hospital.    Shoot me a message and we'll have a conversation on the subject.

Will do.