If you're using a collection validator (using SetCollectionValidator) then the index is automatically included in the property name. However, if you need to perform the validation at the school level then you'd need to write a custom property validator to do this. Take a look at the code for the CollectionValidatorAdaptor (https://github.com/JeremySkinner/FluentValidation/blob/master/src/FluentValidation/Validators/ChildCollectionValidatorAdaptor.cs) - this should give you a starting point for writing a custom property validator that is aware of its place within the collection.
Hope this helps
Jeremy
