Combine N different meshes with M different materials on each

The situation is as follows: input parameter(meshFilters) - are parts of the pattern of clothing (such as the sleeve, back, front), they all differ from each other and all have N different materials on each.

The task: to unite all the meshes into one, keeping all the materials on each piece of clothing.

At the moment I have such a code. Output mesh uses standard material. But we don't know in advance about the number of parts and the number of materials on each of them.

     public static void MeshesToFile(List<MeshFilter> meshFilters, string filename)
 {
     Mesh resultMesh = new Mesh();
     GameObject GO = new GameObject();
     MeshFilter MF = GO.AddComponent<MeshFilter>();
     MeshRenderer MR = GO.AddComponent<MeshRenderer>();
     CombineInstance[] combiners = new CombineInstance[meshFilters.Count];
 
     for (int i = 0; i < meshFilters.Count; i++)
     {
         combiners[i].subMeshIndex = 0;
         combiners[i].mesh = meshFilters[i].sharedMesh;
         combiners[i].transform = meshFilters[i].transform.localToWorldMatrix;
     }
     resultMesh.CombineMeshes(combiners);
     MF.sharedMesh = resultMesh;
     MR.sharedMaterial = new Material(Shader.Find("Diffuse"));
 
     MeshToFile(MF, filename);
 
     Object.Destroy(GO);
 }

How can I do that?