I would like the ability to force a page to use a Parent Page based on the content of that page.

For example, a long document might have several chapters and the chapter title or chapter number uses a specific paragraph style. That style could include an attribute to apply a specific Parent Page to the page the text appears on, allowing the designer to automatically select the chapter start parent where appropriate. As the text reflows the parent would be removed or reapplied as the text moves from page to page.

Sometimes a paragraph might span a page break, putting the start of the paragraph on one page and the end on another. In the example above that would not happen, but the feature needs to accommodate all possibilities. Imagine the attribute is applied to a paragraph that starts on page 12 and ends on page 13. Options could include to apply the parent to all pages containing the paragraph (both p12 and p13), only the page where the paragraph starts (p12) or only the page where the paragraph ends (p13).

The Pages panel would show the parent applied with some highlight indicating the parent was selected automatically (perhaps in italics). The page would remember the parent that was normally assigned to it and would switch back to that parent if the triggering paragraph moves, is deleted, or is formatted to remove the attribute.