Hi @yavoredipov, welcome to the community! When you get a chance, please introduce yourself here and maybe add your picture.
The idea of grouping forms is an interesting one. We added filtering and searching to all form lists a few months back it sounds like you need more than that. What high-level problem are you trying to solve with grouping?
And as far as the approach, do you have the code in a branch somewhere we could look at it?