Constrain in script with related records?

I'm trying to script a phone directory. I start with taking the user to a layout in find mode with the possible/relevant fields to specify the people to be included. The script then performs the find, but before displaying the results, I want to constrain the found set further by specifying that this is the phone number marked as preferred for directory use. Contact numbers are stored in a separate table from names and addresses and each individual might have anywhere from 1 to a half dozen or more phone numbers, email addresses, etc. On the main data entry screen I use a portal to create these phone/contact records and include there a checkbox to specify if the number is to be used in a phone directory listing. But I get a "no records found" error when I run my script. What am I doing wrong?

My script looks like this:

Perform Find []

Go to Layout ["PhoneDirectoryDisplay" (PeopleMainTable)]

Constrain Found Set [Restore]

Sort Records [Restore; No dialog]

Enter Preview Mode [Pause]

In the *Constrain/restore* step I specify:

PhoneContactNmbrs::phoneDirectoryYes: [=yes]

Thanks for your help,

decker