Displaying "grandchildren" of parent items

[LM7]

Sometimes I have a parent item with children, each of which itself has other child items. For example, I sometimes divide a project into sub-projects, which are its child items, and each of these sub-projects in turn has its own child items - the steps necessary to complete each of these sub-projects.

Is there any way to formulate a search (presumably, an advanced search) in a manner which would automatically display all of the children and "grandchildren" of the original parent item, without having to manually specify the titles of the children of the original parent (e.g., Subproject 1 and Subproject 2) in the search request?