Variations of the circle packing example in the Convex-Concave procedure


I have been making some changes to the circle packing example. First I have tried to do the circle packing in a circle instead of the square making something as:
and it works fine, being x and y the center position of each circle and R the radius of the big circle where the small circles are enclosed.

But I have tried to do it in a different geometric shape as the area defined by two circles with equal center and R2>R1:
but the lower bound makes the problem not convex.

Is it possible to reformulate it in a convex way?

Thank you very much

No, it is not possible.