Method to get grandchildren?

Example structure:

Parent
|.   |-- Child 1
|.       |-- grandchild 1
|.       |-- grandchild 2
|.   |-- Child 2
|.       |-- grandchild 3
|.       |-- grandchild 4

Is there a way to reference the grandchildren from the parent? So for example, I want to build a template for the parent that pulls in the grandchildren, without having to do it manually. Is there a method to do this?

Perhaps site.RegularPages can help e.g with a structure of content/parent/child/grandchild.md

{{ range where site.RegularPages "section" "parent" }}
<a href="{{ .Permalink }}">{{ .Title }}</a>
{{ end }}

But let’s see your code for a better insight.