Expandable/ collapsible multiple answer list

Hello, I have created a multiple answer list with > 50 choices in ca. 15 categories. The participant must enter a % value next to some of the choices, and the total should be 100. I would like to make the list of answer choices below each category label expandable/collapsible upon demand, so that the user doesn't have to scroll through all of the choices all the time. I would, however, want the user to see all the categories at once, without having to scrool (too much). Here is what it looks like currently: ! Any ideas how to get this done? Thank you!