Add three boxes layout to autolayouts in Impress

I am really fond of autolayout, but since I work mainly with 16:9 slideshows for art and architecture presentation, one of my standard auto-layout would be to have three boxes side by side and not just two. Is there a way to add new autolayout? I am not talking about the slide scheme, I need to add a new one to the existing 12 layouts
I am working with Impress (64 bit) on Windows 10 in Italian, so I hope the translation of items is correct.