Filtered dropdown list across multiple records using multi-keys

Discussion created by ucharles on Jun 3, 2018
Latest reply on Oct 22, 2018 by ucharles

I took a great deal of time to study ISO Magazine tutorials provided by Matt Petrowsky. I would recommend them to every Filemaker aspirant. I am interested in the dropdown across multiple records that would eliminate all options selected in one record or another. In the attached file the dropdown list is working ok as it should; it eliminate Devcons that each person has attended from the dropdown list so that only the Devcons that that particular person has not attended is available.  I want to adapt the dropdown so that it eliminate every Devcon selected, by one person or another, not be available in the dropdown list across multiple records. If one person has selected all Devcons, then the others would have nothing to select.