Creating Adobe Experience Manager Components that use Nested Multifields

You can develop a custom Adobe Experience Manager (AEM) component that uses a nested multi-field control located in a dialog. A nested multi-field control is an inner multi-field control within an outer multi-field control and lets an author dynamically enter data. For example, assume the AEM control lists developers and each developer has an unknown number of skills to display. That is, within the inner multi-field, the author enters details such as a professional skill set. The outer multi-field determines how may developers to display.

adobe community: https://helpx.adobe.com/experience-manager/using/nested_multifield.html