Hi Michael,
I am afraid this would need an additional custom javascript and CSS code as well in combination with the previous one. It shouldn’t be too complicated though, but definitely some decent work to get it right. I don’t think I can do this one for you, I am sorry (I am really far behind my development work at the moment), but I can recommend a service that may be able to help you out (I am not sure if I recommended them before). They are a team of dedicated WordPress developers, so far I have not heard any negative feedback.