This circular buttons can be tricky and I can see (at least) 3 solutions:
- Use Circle shapes and “is tapped” trigger, put the largest one at the bottom and stack them.
- Use multiple buttons per circle, as explained in this article Irregular shaped clickable object - #7 by tosolini by @tosolini
- Use SVG through an HTML Frame as explained in the same article, but further down in the posts: Irregular shaped clickable object - #25 by Joshua (link should go to the US map buttons). This one is a bit more technical to retrieve the clicks as triggers in the experience, but gives you the most flexible design.