Late to the party here, but better late than never, as they say (just as long as the alcohol is still being served!). Since I’m late, I decided to go straight to the end challenge.
One track per circle, 3 filters per track, but I haven’t yet worked out how to respect the rounded ends on the lines (I suspect my method is very similar to @Elusien, and that part involves a mask, which might be problematic).
Special characters to do the circle entered my mind for a brief moment but then I opted out.