I’m working on a similar problem, and I’m a bit stumped too. As far as I can tell Bricks doesn’t have a built-in element that does this - I’m a beginner at this stuff, but it’s been a month since your post and nobody else has written with any suggestions either.
The three broad strategies I can think of are:
a) Use tabs instead of radio buttons. Have people select the tab that reveals the desired version of the form. This is what I’m thinking for my purposes, but I guess it depends how many radio button options you had, and it would probably only work for one layer of choices.
b) The most elegant UX solution is to add some manual javascript and/or CSS to reveal hidden elements based on radio button clicks. I’m too much of a hack to code that easily myself but it’s almost certainly doable with some web searches for tutorials.
b) submit the form with just the radio buttons on it, then use conditions to choose which form page to display next (thread where someone is wrestling with how to do this: WAIT: Conditional logic show/hide error And-or logic - #5 by simplecreative). The UX is worse this way because it requires more clicks and page submissions (also more pages cluttering up your back end), but has to be doable (though again it would take me some research time to work out how to execute it
Hopefully some of that helps?
Alex