If I understand correctly, you have nodes named firstpage at some places in your hierarchy, and when items are placed in here, you want them shown on the frontpage right ?
What I would suggest is that you make these firstpage nodes related items to the front page. That way, ViewCaching will clear the cache for the front page when a new item is published in one of those related nodes.
Relations are usually the way to go when dealing with ViewCaching.
