核心数据——在不触发错误的情况下，获得对多个关系的目标

I have an entity with a to-many relationship. After I fetch a subset of objects from my entity, I would like to get the ManagedObjectIDs of the relationship objects - without firing a fault. Is this possible? My understanding from the documentation is that calling objectID on a fault does not cause it to fire, but when I try the following line, a fault is fired for each object's relationship nonetheless:I have an entity with a to-many relationship. A