For my purposes I want to apply Group Normalization to three specific channel groups of a tensor. This groups are contiguous so for a Tensor with dimensions (N,C,H,W). Group 1 would be (N, : C /3,H,W), Group 2 (N, C/3: 2C/3, H,W) and Group 3 (N; 2C/3 : C, H , W). I tried looking in the code base but did not find what the logic of group creation  is.
Can someone explain to me the logic for the formation of groups in GroupNorm? Does it match my contiguous scenario?