Can I apply new margins to multiple parent pages?

I'm working on a long book with a parent page for each of 29 chapters, only changing the running head to that chapter's title.

We're adjusting the margins for the whole book, and I would love to apply the new margins, which I've applied to the first chapter, to the rest of the parent pages, instead of making the changes another 26 times.

Is this possible? I couldn't find the answer in the help area.

Thanks!

Susan