Merging layers in Spline Design

Is there a way to merge different objects together in the current state of the spline.design web 3D tool?

Boolean merges will result in multiple objects in the resulting code export which is what I'm trying to avoid. In Figma this functionality can be achieved by merging multiple layers using the Flatten option.

Could not find any options in the tool and no reference in the official documentation.

I found the solution. Merge only two at a time:

1. Shift-select master object, the one with States
2. Shift-select object you're adding to it
3. In right sidebar select "Merge geometries"