Tite Kubo clearly bases all his villains on some or the other group. The first serious villains in bleach were Aizen and his arrancar army which were Spanish themed. Most of the names of the arrancars, their releases and names of key locations in the Arrancar universe meant something in Spanish. I don't know which group in particular he was targeting at but the arrancars had Spanish roots. The Quincy army is clearly based on the Nazi army. The Stern Ritter is closely based on Hitler's SS. The uniforms of the Quincys is also very Nazi in nature. The ideology to set up a powerful and supreme race points out at the Nazi ideology.