Edit: Now that I'm wide awake I realize that the following doesn't directly address your problem, so I better address that...as far as I know when you hide a photo in iPhoto it hides it in the Library, consequently it gets hidden everywhere it lives (Library, Albums, etc.). The only alternative to this that I know of is the following:
iPhoto keeps all your photos in the Library section which you can view by Events, Photos, etc. iPhoto's Albums are similar to iTunes' Playlists. Like a song that appears on multiple Playlists a photo can appear in multiple Albums. The song/photo listed in the Playlist/Album is just an alias to the actual song/photo in the Library. Like in iTunes when you don't want a song on a particular Playlist you can delete it from the Playlist, you can do the same in iPhoto with a photo from a particular Album. It will only be deleted from the particular Playlist/Album that you deleted it from.
As long as you don't delete the song/photo from the Library it will still be available to the other Playlists/Albums.