How can I ensure Unity does not rearrange the sub-mesh order of a mesh from Maya?,How can I ensure Unity does not rearrange sub-mesh order of a mesh?

having a bit of a head scratcher problem here. I have my artist's making multiple unique meshes in Maya that contain 3 materials. Each material is assigned to a sub-mesh in a specific order. This order is identical across all the meshes being created. When bringing over these meshes to Unity, we have noticed that some meshes keep their material/sub-mesh order from Maya, and some do not. It's been making code generated material swaps a nightmare. So a few questions:

1. What is Unity's logic when importing meshes and ordering the sub-meshes?

2. Is there a simple way to make sure Unity does NOT reorder the sub-meshes/material order?

3. Is there a way on Maya's side when exporting to make sure the sub-meshes/material order is as intended?

Any help or ideas is appreciated. Thanks!!