Pick Many-Buttons

I'm trying to create a "Pick Many" which is really a Multiple Answer question using the Freeform Pick Many template. I've created 9 buttons and have a different color for each state (Normal, Hover, and Selected). Since there are multiple answers I would like the buttons to change from tan to grey once they are selected. I've been able to get it to work on one button but if you select the next button it takes the state away and looks like it's not selected. 

Does anyone know how I can get the state to remain after clicking on another button?

Thanks!

3 Replies