Looking for an Easy Way to Produce a Delayed RSS Feed

We’d like to have an RSS feed that always contains our blog posts except those posted in the last 12 hours. We’d use it for our NewsTex syndication to Lexis-Nexis, so that we’d have several hours to correct errors and provide updates, before our posts are permanently archived there. Is there an easy way of doing that? I’d much appreciate your suggestions. Many thanks!