I am trying to create mixed elements in the parent RecyclerView, inside it, contains some CardViewswith another RecyclerViewinside it. If you still do not see it, imagine a few ListViewsinside RecyclerView(this ListViewswill be grouped by the header).
Here is the structure I drew to make it clearer:

Above is the layout structure I'm trying to achieve. Please note that this is only planning. I'm not sure it's nice to have a RecyclerView in a RecyclerView.
ExpandableRecyclerView . , RecyclerView (, ) .
. - , ?
, RecyclerView CardView RecyclerView, , .