Sounds like you need record level access control.
See "Editing record access privileges" in FileMaker Help and check out this particular sub section: "Entering a formula for limiting access on a record-by-record basis" for a description of how to set this up.
Note that with this setup. Any find performed automatically omits records that the current user's access permissions do not permit them to view.
Totally forgot about that. Thank you for saving countless hours of life!