Relations between two EdmEntityType in oData Web.API

Hi
I'm using web.api oData and greate my data model with dynamic with EdmEntityType. I can read the oData-Stream with Excel Power Query, but have to add the relations between the EdmEntityTypes/Tables.
I'm now testing with EdmNavigationPropertyInfo, but can't set the info in model in that way, that Power Query could read the relations.
Simple example:
EdmEntityType Product and ProductGroup
Type Product
ProductID
ProductName
FK_ProductGroupID

Type ProductGroup
PK_ProductGroupID
ProductGroupName

I can read this two types and connect Product/FK_ProductGroupID with ProductGroup/PK_ProductGroupID by hand.
Can I create this relationship directly in model? How can I define that die FK-Field und PK-Field are connected?

Best regards
Christoph