Samurai kit...

I was reading a few ideas on the topic and found something I liked. It was focused on dual-wielding one katana and one wakizashi. It said was as long as they were using these two weapons together they were treated as if they had the Two-Weapon Fighting feat. I know there are no feats in the BG series, but would there be a way to make a class where so long as they used a katana and wakizashi they would effectively have the benefit of 3 pips in two weapon style? Also, later they get Greater Two-Weapon Fighting feat, is it possible to add a second offhand attack?

This was the page: http://dnd.arkalseif.info/classes/samurai/index.html