Repeating Group - Constraint by Matching with a List of Things

I want to add a constraint in a repeating group search criteria where a certain attribute (another Thing) should be part of a set. For example, show all Students from a certain set of High Schools, where High School is an attribute of Student and a Thing in itself.

Any pointers / guidance would be great!

Awesome! Get at it mate

Lol, would love some help on this.