The section Blocking Changes gives an overview of the methods available to prevent given revision from merging.
EDIT:
To my understanding subversion is all about revisions. In contrast to well known DVCS it does not track content or change sets. In order to close the gap between tracking a file in subversion, but not tracking deployment/working copy changes, the following approach might be feasible.
Instead of 'id.txt', a file called 'id.txt.template' is versioned. As part of the deployment process, 'id.txt' is generated, while being part of svn:ignore
.