I have two data sources:
AccidentReport = this is a new form and is completed whenever someone has an accident at work. One of the columns in this data source is called “BeenInvestigated”, which is set to false by default.
InvestigateReport = This is a new form and is completed whenever an Investigator decides to looks into the submitted accidents from the AccidentReport list.
When an accident has been reported, it appears in this dropdown to be investigated:

This is the dropdown’s items property:

I would like to know how to remove the AccidentID from this dropdown, as soon as the InvestigateReport form has been submitted. For example, if AccidentID 38 has been investigated and sent to InvestigateReport as a new entry, I would like 38 to disappear from this dropdown.
It would be great if I could update BeenInvestigated in the AccidentReport to true for that record when the corresponding InvestigateReport form has been submitted, but if there is a better way to do this, I’d be happy to hear about it.