Unreal Editor 4 Export

Hi,

Does anyone know how to create material ID’s for an Export File (FBX Format) consisting of multiple Objects (Head, Eyes, Teeth…)?
In Max I can assign a Multi Material and set the according Material ID’s in the Meshes so that I can specify how many Submaterials an Object in UE gets and which Material gets which Material slot.
Is there a way to achieve the same in Blender?
I assigned different Materials to the Objects but have no Influence on the Material ID Number to specify which Object gets which Material Slot.

Cheers Christian