Leader Blocks and Multileaders

Hi everyone!!! Recently I been creating some custom Leaders with c# to automate my workflow a bit, and I was wondering if there is a way to add blocks to the leaders in Rhino, like the circles or different shapes surrounding the text, not just the rectangular text frame. Something like this:

Capture4

If this is not possible by default, I also wonder if there is a way to extend the geometry of the leader class with c#? I know you could do this by grouping the geometry, like in this thread: Is there a multileader option in Rhino? - #5 by Helvetosaur, but I think it would be awesome to be able to add some custom parametric blocks to the leader so the we can modified the block appearance by using the leader properties menu, but I’m not sure if this is even feasible using c#. Thanks!!!