It seems unusual that you have separate tables for each product instead of storing all the data in a single table with different groups of records for each product, but since some else set up the database...
Define a calculation field like this:
Product A Table::Warranty Info & Product B Table::Warranty Info & Product B Table::Warranty Info
And select "text" as your return data type.
This "glues together" the contents of the three fields into one. Since only one field contains your data and the others are blank, it should display the data the way you want.
That was too easy, missing the forest while looking for a tree kind of thing
Thank you very much.