Scripting the grouping of objects

Just getting started with scripting OmniGraffle and have success with creating shapes, lines and text, and selecting a group of objects by name.

The next task is to create a ‘block’ made of multiple elements, turning them into one named group which can then be moved by the user or another script. Essentially, I need to call or replicate the menu Group command but can’t seem to find a method to do this with JS.

Any help appreciated. Thanks!