As far as I know, there is not direct trigger or API based on the fact that a Bookmark was selected. I'd recommend thinking along the lines of testing the results of the Bookmark Selection - for example, certain selections in fields, etc...
If you are in total control of creating your Bookmarks, you could possibly associate certain Variable values with your bookmarks and condition your Objects Show criteria based on the value of the Variable. Might be a long shot, but worth a try...
