Birthday toy chaos

Our 1 year old had her birthday party last weekend and got some new toys! She really has never had anything “new”, because other than a few toys here and there, I’ve just been recycling my first’s toys. My 3 year old is struggling hardcore with the fact that her sister has all of these new things. She wants to play with everything and is getting upset with her 1 year old sister if she is playing with something. She is a great sharer otherwise, but these birthday toys are very hard for her lol. I feel like all I’m doing is policing these damn toys. What are some ways that you’ve helped your older child understand that their sibling can have new things and not everything belongs to them (when it comes to presents)? Again, sharing has never really been an issue with her. Thanks mamas!