Xgboost rank:ndcg learning per group or for all dataset

I'm trying to implement xgboost with an objective of rank:ndcg

I want the target to be between 0-3.

In my data for most of the groups, there is only 1 event per group which his target is not 0.

I wonder if the model will learn different about this product when I put target value 3 (and not 1) when this is the only target that larger than 0 from products on a different group which got target value 1. or it is learning per group id and if the in the group there is only one target larger than 0, it doesn't care if it is 3 or 1