Sub-scroll doesn’t scroll with parent at top or bottom of frame

In my Figma prototype, I have a sub menu (set to scroll vertically) within a main screen (also set to scroll vertically). The sub menu scrolls and so does the main page, but when the sub menu reaches the top of its scroll frame, it does not assume the main scroll behavior to go up the main page. it comes across as broken to users at the top and bottom of the scroll. How do I fix this?