Making the main link stay in hover position while still on dropdown menu

I’m using a tweaked out version of TwentyTen using the access menu system and I’m noticing something interesting. I’m using image sprites to be used for the main menu so of course, hovering over them brings up another image or in this case, same image but different position. That works, but when I roll off the button but I’m still on the secondary drop-down navigation, the image rotates back to its’ original state. Isn’t there a way I can keep this in the hover state until I’m off both the primary and secondary menus?

Here’s a site I’m using it at: https://www.fashionweeknola.com/

Rollover a button like Retailers and then move your mouse into the secondary area and notice the image goes back to its’ original state.