As the search queries did not always relate to a single person, but often to an entire family, the CLI index cards provided lines for a maximum of six family members of the main person being searched for. Information on names, relationships to the main person, place and country of birth and the last known address could be entered here.

A blue or green Cross Reference Card (XR Card) was created by the CLI for each family member listed on the index card and sorted into the card index. Each family member could therefore also be found directly in the card file, i.e. without having to go via the card of the main person (Master Card).