Provide a title pattern for Book Outline

I have recently started using this module and think that it is great. I would love to have a Book Outline pattern added as an optional configuration. The Book Outline pattern should be used instead of the Book Page pattern on book page nodes that are the root node (outline) of a book.

I have a page title pattern setup for book pages:

[node:book] | [node:book:root] | [site:name]

This works wonderfully to display

Book Page | Book Title | Site Title

However, on a book outline node it displays

Book Title | Book Title | Site Title

Since book title and page title are the same on this node.

I would love to be able to specify a pattern to display

[node:book] | [site:name]

Only for book outlines.