I only have Kupipi, Curilla, and Ayame available on my server at the moment. Kupipi has the ability to cure members of the party including other trusts. Right now my server is going to be open to limited beta this week (finally) so you will be able to see them in action first hand.
You will most likely have to code it from scratch. My server is running off the old AI implementation before it was redone. I took what another person did for their server who was able to get trusts into the party and I expanded on that by increasing the AI functions so they do a lot more than what retail did. I have a very large custom AI code in the core that handles all of the trusts decisions from cure casting, to WS usage and JA's. It took me a few months to get everything set and I borrowed heavily from my pup AI code and expanded upon that and I am in the process of adding more trusts and polishing the AI's for the other 3 trusts that are available on the server currently.
I probably will take a look at the latest core AI and see what can be done. I understand a lot of the AI concepts for Trusts and AI so I could probably get it as close to retail as possible (my trusts are a bit more advanced than retail as they do a lot more) and if approved maybe contribute to the code.