Sounds to me like you might want to investigate Record Level Access in Manage Security. It allows you to apply a calculation to determine if someone has access to a record. A common formula is to compare Get(CurrentAccount) to account creation auto-entered field that should be in every table. This allows only people who created the record to see it.
Some more on Record Level Access:
your expression can compare the user's account, privilege set, or list of extended privileges to either a field in Table A or a list of value from related Table B records.
Any find performed by script or manually automatically excludes "no access" records from the resulting found set.
Thank you for the replies. I'm still not sure how to execute a list calculation on related records based on a search for a specific string.
It's hard to say for sure but I don't think you need to create a list. I would highly recommend investigating Record Level Access.