Hi Andrei,

> Michael, I'm not sure I understand how this method works.

I mean that if you have an object like this where the surfaces are joined together, here with a face sub-object selected:



Then when you extrude that (again, those surfaces are joined, not independent and it's one face sub-object of the full object selected), I could remove the base surface and automatically make a joined result like this:



So the main way to trigger this would be to join the pieces before doing the extrusion.

- Michael