Possibilities to merge a detail variable?

Hi everyone,

Today I encountered a problem because of lacking data from a universe.

Explanation in this Excel sheet below:

I already tried to make a dimension that =[detail variable] but I can’t merge that with dimensions from the Universes either…

So now I have nothing to merge from Universe 3 to retreive the Vendor Name.

TL:DR - How can I merge a dimension and a detail variable?