Revision links in subprojects without repository
All our code is managed within a single svn repository with the default /trunk /branches /tags layout.
In redmine we have a main project with a repository.
We also have subprojects where each subproject represents some kind of major software subsystem. These subprojects do not have a repository - redmine seems to duplicate the changeset data for each subproject if we do setup a repository.
Is there a way to get revision links (e.g., r123) in issues etc. raised on the subproject to display links to revisions on the parent project's repository? Without a repository on the subproject the links are present but not activated.