Dynamic control on tooltip pop-up?

Hi,

I have a report I'm building and on some rows there's additional comments. The data this is related to is basically like:

Type of Metric     Variance Value     Variance Comment

Comments aren't always required though, so only specifics values have comments. It's easy enough to highlight those through conditional formatting, but I was to make it easy to view the comment. I like the look of tooltips, but it seems like, at best, I can only restrict tooltips down to a column. Is there a way to make it so the tooltip will only appear on hover when that variance comment field isn't blank?

Thanks for any help, even if it's just to tell me that the answer is no. 😀