I’m trying to build a custom projection to allow end users to run queries directly on Customer Info Address.

I was hoping that I could link back to the Customer Info record via Entity Associations such that the end user would be able to query properties of the Customer Info record as well, but it defaults to a collection type, when it really should be a single reference, preventing me from using it as an $expand property in the OData service. 

Is there a way to adjust this, or am I going about this the wrong way?