I would duplicate the first stream and then whenever the leads become exhausted, send them to Stream 2, which has the same content.
I've seen people do this before and I would recommend avoiding it whenever possible. The better practice is to move content around, add content, etc. You can also Pause leads for a bit, then restart less active ones. Or better yet, pull people through a funnel instead of just sending them a list of content. People who don't respond get put on a slower or different track.