By the sounds of it you want some sort of mouseover effect adding to the combo menu dropdown, but so far it's vague...
Maybe put a screenshot/mockup together of what you want to achieve and I can suggest a solution for you / create you a custom widget...
Navigation hover effects usually require some extra CSS and/or JS code.
There are some promo widgets already built-in, but you do need
at least basic coding knowledge to use them.
Examples.