Book file and text anchors

Thanks to the help I got yesterday, I have now knitted a book. I'm going to have some cross-references from one chapter to another. Within a single document, I know how to do that. I create a text anchor and then hyperlink to it from another place in the document.

Today I created a new text anchor in one chapter. When I went to the other chapter to create the hyperlink, the text-anchor box did not show any text anchors. (That chapter had no internal links.)

So I think my question is how I get the indb file to "know" the text anchors in each chapter. Is there a way to import them?