Hide collection and items on items-browse and collections-browse

We want to do a mass import from another repository but don't want to reproduce their whole repository. Basically we want to use the images only for exhibit purposes, while maintaining the original content owners as the sole public providers. Here's what I'm thinking...

1) Hide/exclude a single collection and all of its items in the index page, item browse and collection browse pages.

2) More difficult, maybe. Hide/exclude the same items/collections from the search engine.

3) I might be able to avoid the issue altogether by creating custome exhibit templates. See related post here: http://omeka.org/forums/topic/creating-custom-exhibit-templates-for-external-items?replies=1#post-1594

As always, thanks for all the help.