It’s possible. It won’t be quick, but it’s definitely possible. Depending on your needs, there may be other ways of handling it, but not sure what your exact use case is.
This is very doable. It’s one thing I’ve been able to do quite reliably in Bubble.
Here’s a snapshot of an RG within RG. Obstacles can be added to the top RG using the input and button at the bottom. Possible solutions can be added to any obstacle using the input and button within any Obstacle cell. The added solutions are then shown in the nested RG.