Sorting container by page-link title field

I am displaying container list entries with the pagination tags and 
sorting. One field in the container is a page-link. In the table I am 
displaying the original title of the page, but when I click on sorting the 
table by this field, it sorts the page-IDs rather than the page titles, 
because the "value" of the field is the page-ID. 

How can I sort by the page title?

Benjamin Papez