So whats the number? How many would you consider a significant part of the whole group?
A significant part. It's largely up to the beholder, I would expect. Intuition.
Also what is your position when say 300,000 of them are killed, not with the intention of obliteraating the group, but as a demonstration of power? Or because they could?
An interesting question. Mass murder, probably.
Genocide is the deliberate and systematic destruction, in whole or in part, of an ethnic, racial, religious, or national group.
While precise definition varies among genocide scholars, a legal definition is found in the 1948 United Nations Convention on the Prevention and Punishment of the Crime of Genocide (CPPCG). Article 2 of this convention defines genocide as "any of the following acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group, as such: killing members of the group; causing serious bodily or mental harm to members of the group; deliberately inflicting on the group conditions of life, calculated to bring about its physical destruction in whole or in part; imposing measures intended to prevent births within the group; [and] forcibly transferring children of the group to another group."
http://en.wikipedia.org/wiki/Genocide
I have no doubts on that score. I'm simply comparing it to the Allied forces employing their own Judenrats under similar circumstances and then attempting to deflect responsibility.
For your inference to be accurate, you would have to first define it as a genocide. Is it one? I'm open to your arguments. And why drag Australia into this?