multiple criteria filtered portal

I can't figure this relationship procedure out...

I have two occurences of the same table: AllParts and SomeParts.

I want a portal (showing SomeParts records) to list only the parts that meet certain user-defined criteria the user has set using global fields.

For example, the user selects color="green" from a pop-up, category="bolts" from a second pop-up, and vendor="acme" from a third pop-up. So I want the portal to show only the green bolts sold by Acme.

Here's what I tried unsuccessfully:

- added a global "criteria" field that contains a shorthand code for the user's selections.

- added a calculated field that generates the same shorthand code for the record's properties

- created a relationship between the two table-occurences that matches the allparts::global to the someparts::calculated fields.

I can see the fields contain the correct values and should have plenty of exact matches, but nothing shows in my portal.

Am I going about this wrong way?