How to do will with property in NSW and one in China

[Pei Nim Lam]

I hope someone can help me, I have read posts in "Wills and Estate Planning Law Forum" but not much about having property in China.

1. I want to find out if I need two wills, one in Australia and one in China due to properties in both countries?
   
   
2. What is the benefit of having 2 wills? Will it stop residents in Australia to contest the will in China and vice versa?
   
   
3. The property in China goes to my sister who lives in USA, I don't want anyone in Australia to contest this will as it's a family property. Whereas the property in Australia can go to my partner etc.
   
   
4. I heard about International Will, should I go for an International Will or will that complicates matter? I hope one will solves my problem but I need advise especially when someone contest my will regarding the China property.
   

Any advice is much appreciated and I live in New South Wales, property in Australia is also in NSW to avoid complication between states I believe.