Thanks Peter - I think that as a creator you can understand that if you set some specific guidelines about your work you feel that it's warranted. There really is nothing I can do, but when I see it in our forum I can not help. Purchasers, although we are not explicit about it, do get help first around here (as best as we can). The admin are able to know this information...
To answer your question, right now there isn't a way to do what you are asking. We would need to add yet another button along the lines of "hide from visual index" and we're not ready to do that. I am aware of this particular scenario and I don't have a solution myself...
We already need to revamp the 'sections' media source, or add a new one, because the current one doesn't do the job completely.
But, there might be another way. Make a hidden section, don't publish the section page, move your exhibit to that space and then create an Exhibit Link with the url to your hidden exhibit and it might work. I realize that's a little complicated, but Exhibit Link's were partly created for these unusual circumstances (I've seen many of them over the years).