Isolating records in a value list
I have a three table data base and a JoinTable. Two tables (Country and Denom) create a join table (CountryDenom) and then link to a third table (TypeVariety). See image file. In the TypeVariety layout, I want to link a CountryDenom ID in a two step process, first by selecting a country from a value list (at this point the 1st field value being CountryDenom:ID; second value field being Country:CountryName). While I may have many Countries, not all are joined to a Denom in the CountryDenom join table. But when I pop the value list, all countries appear in the list, even if they are not joined with a Denom in the CountryDenom join table. How can I isolate only those Countries in my value list such that it lists only those that are in the join table and not all the Countries in the Country file?