If you create a standard epub, such as what Apple's Pages generates, this type of navigation is available by default.
If you want this scheme in iBA, I think you'll need to create two links that point to each other for each example.
That is what I did (I am using iBook Author) and it seems to work in iBook Author but when I preview this on the ipad it does not behave the same. I think this must be a bug on Preview.
In the iPad when I touch the hyperlinked bookmark it returns to the previus page and not to the original bookmark.
If you think there is a bug in preview, Share/Export as an .ibooks file, then drop it onto iTunes, then sync to your iPad and test as a release version.
And instead of linking to each other, create two bookmarks and two hyperlinks... 2 pair instead of one. They will need to be right next to each other and you'll need to label them and I think that ruins the final product, but hey, that's just my opinion - good luck.
Ok just figure out a work around
I looks that it happens when reference are circular.
What I mean by that is that if I am hyperlinking to a bookmark and the book mark is hyperlinking back to the original hyperlink then that causes problem with preview. I try hyperlinking back from the bookmark to something else other than the original word and that worked.