Perfect! I understand now. Thank you for offering more information about your project.
Personally i think it would be a great feature to allow the default urls to be used as the default link to the pages (makes sense to me), in addition to this it would be amazing if, when a pages default url is changed, all site links to this page change to meet the new default setup.
I think we agree on this. Georgi wrote in your other thread that LinkManager does not currently consider additional or preferred URLs. This feels like a problem to me.
To your other point (about retroactively correcting all web site links if the URL is changed); this might be tricky. One thought I have is that LinkManager ceases to use URL's and begins to base the link on the Guid of the page.
Prior to the page being rendered to the browser, this Guid would be converted to the page's default URL. This would allow you to make massive changes to the URL's and web site structure without any negative impact to the underlying web links.
The Sitefinity team would know better than I the performance and technical impacts of this approach though...
An intercept class might be your only option for now. Perhaps other have a better suggestion?
Certainly let us know if you manage to solve this!