Transform mesh while combining

I want to combine mesh from Transform 'A' to Transform 'B'. To achieve this, I use this code:

 MeshFilter[] meshFilters = A.GetComponentsInChildren<MeshFilter>();
 
 CombineInstance[] combine = new CombineInstance[meshFilters.Length];
 for(int i = 0; i < meshFilters.Length; i++){
 combine[i].mesh = meshFilters[i].mesh;
 combine[i].transform =  meshFilters[i].transform.localToWorldMatrix * B.worldToLocalMatrix;
 }
 B.GetComponent<MeshFilter>().mesh.CombineMeshes(combine);

'A' has children on multiple levels. After I run the code, nothing appears in Transform 'B'. I guess it has something to do with wrong transformation matrix handling. How do I make it work?