Cross-Company Customer Look-up for a Customization

We’re using Epicor 10.1.400. We have multiple companies and each company makes parts for the other companies. These parts are all quoted, some may get actual Part and Method master records, some may be ‘on-the-fly’. My boss would like to be able to determine how many quotes/parts were quoted by our Company A to our Company B, and also the end customer for these parts. The first part is simple enough, but the end customer is a bit more complex.
I was thinking of adding another field to the Opportunity/Quote Entry form that would be a lookup of the Customer table for the ‘quoted to’ company. I’m just not sure how to do the cross-company lookups.
Or maybe there’s an easier method?

Why not make a cross company BAQ that looks for orders placed from one company to another and where the part exists in the other company? The BAQ could return which company was the owner of the part…

Thanks. That should work.