If you set up a calculation field with this expression:
list ( FieldA ; FieldB ; FieldC )
and use this calculation as a match field in a relationship. It will match to records in the related table by fieldA or fieldB or fieldC.
A single field formatted with checkboxes boxes or a join table could also be used.
I have a TO called MEMBERS with all the data I need for this particular task.
I want to create a new layout (and TO) called Search_LastName_FirstName_MemberType, that will search for matching data in three fields in records in MEMBERS.
I created the new Search TO and layout with fields LastName, FirstName, and MemberType to match with those in the MEMBERS TO. I also added a portal with the matching fields from the MEMBERS TO. (The fields within the portal pointing to MEMBERS TO fields don't appear in browse mode, BTW--another mystery. I've tried sending the fields to the front but that didn't work. I have another working portal in another layout that works fine and I can't see any difference in the setups. That's another problem, however.)
The TOs are related by a member ID field.
When I create a new record in the Search Layout/TO I want to be able to enter data in FirstName, LatName and MemberID and have the portal show any and all all matches from the Members TO, not just records that have all three fields matching but any that have even one matching.
"(The fields within the portal pointing to MEMBERS TO fields don't appear in browse mode,..."
The most likely reason is that there are no records in the related table that match to your current record on your layout.
Simplest method for getting your list of records would be to not use a portal. Just put three global fields on your layout, enter/select your search text in these three fields, then perform a script that sets up and performs a find--displaying the results on a list view layout based on the table you want to use for your portal.
If you really must use a portal, you can either use the same method, but after finding your records, you set a match field to a list of the primary keys or you set up a Cartesian join for your portal and use a filter expression to control which records appear in the portal. This last option can require a pretty complex filter expression and be slow to update if your portal table has large numbers of records.