It should be relatively simple to add support for saving links inside Page xproperty by adding it to the code here: https://github.com/xwiki/xwiki-platform/blob/e80dcb59f2f8347b2d3cd24ded3d260ceacf6a3b/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/doc/XWikiDocument.java#L5749