field value change based on two other tables

[BrackAttack]

I'd like to add a dynamic field into a database of names.

table 1: dates

table 2: names

table 3: dates & names

while I am looking at table 1 layout (dates), I'd like a field in table 2 to somehow signal that a record exists in table 3 that matches it's name and the corresponding date from the active record in table 1.

example:

table 1:

5/02/10

table 2:

John - YES

James - YES

Mary - NO

table 3

5/02/10 - John

5/02/10 - James

5/14/10 - Mary

5/26/10 - Jonh

5/26/10 - Mary

then if table 1 changes records:

table 1:

5/14/10

table 2:

John - NO

James - NO

Mary - YES

table 3

5/02/10 - John

5/02/10 - James

5/14/10 - Mary

5/26/10 - John

5/26/10 - Mary

How is this possible?

FYI, my ultimate reason for wanting this is to be able to filter a portal. I already have a portal on table 1 layout that lists all names from table 2. But I only want it to list names that do not have a record in table 3. If a matching date/name combo exists it will omit that name from the portal.