How should I present the ability to semi-copy a parent for cousin items?

I'm designing a UI where 90+% of use cases fall into the following two categories:

• All children share the same parent element
• All children belong to one of several distinct parents with little to no shared attributes

However, there's a third case (roughly 5-10% of cases) where children fall under one of several closely-related parents. In this case, the parents share all but one or two attributes.

When entering the previously mentioned common cases, each parent item on the form expands to enter children items under it. There's a [+] at the bottom to add a new parent (which then expands to accept corresponding children). This presents a clear separation of parents, and clear link between children and respective parents.

In the edge case, however, I'm unsure how to present the option to "mostly-copy" a previous parent. My initial thought is to have a traditional copy button (two sheets of paper) next to each parent that will create a new parent below with all the same attributes pre-filled, and allow for similar entry of children items (and editing of the pre-filled attributes).

Is my initial thought the best way of accomplishing this, or is there a better way?