UR supports multiple tabs, and you can hoist and lock each tab to a particular location in the tree. So you can use a single .urd file (database) and tabs to achieve the page level views. This also allows for focused searches (narrowed to the hoisted tree) as well as global search across the entire database.
https://kinook.com/UltraRecall/Manual/hoisting.htm
https://kinook.com/UltraRecall/Manua...viordialog.htm
https://kinook.com/UltraRecall/Manual/tabmenu.htm