[Koha-oz] Koha in schools: group patrons by class?

Hello everyone, I work in a primary school library in Melbourne, I'm looking at transitioning our library system from Oliver Junior to Koha. We have set up a test system to play with settings and so on, and I was hoping someone might have an idea for this. I want to be able to group students by class (e.g. 56A, 56B, 56C, etc.) for the purpose of finding them for checkout, and for grouping overdue notices. I thought of using a custom patron parameter, but I was wondering if anybody had a more elegant solution available. Thank you, Kind regards, Michael Barry.