Title with subtitle as olink generated text

["Zbyszek Cybulski" <z.cybulski@gmail.com>]

Hi list,

I would like to use link to PDF documents using olinks.  That's reasonably easy to do. I would like to create links that consist of title and subtitle of the book. I am referring to a book, not a chapter or a section. As generated text, the olinking machinery gives only the title of the book.
Is there any way to reveal the subject of the book?
I cannot combine the title and subtitle into a single title due to formatting issues. Namely, the subtitle should differ from the title and should be placed in the next line, under the title (as it is by default).
To complicate things, I'd love to see title and subtitle combined into one line, when I inspect the PDF properties. 

Thanks in advance,

-Zbyszek