Hi Abdallah; this is definitely doable. I see that you posted a similar question earlier here in the forums and there were a few answers there as well as a link to some sample code.
Out of my head, you can create a Playlist that contains one or more PlaylistItems; and you can load this playlist onto a Stream. You could create a new playlist every 12 hours, or even after every item, and load the new playlist onto the Stream (therewith discarding the old playlist). Alternatively you could maybe (I’d have to check that) create a playlist once and keep adding items to it every 12 hours (or more often)
Ping me if you need further help (I’ve developed with Wowza for almost 20 years and written 100s of plug-ins)