I have manage software licenses in Google Sheets.

In my sheet Licenses I have a table that lists all the software licenses we manage and their associated info.

1. Each row is a separate license
2. Column A, Selections, is made by joining the Application name from Column B with part of the License number from Column D. I use Selections to populate a dropdown list in a separate sheet Clients
3. If a License is in use by a client, Column F In Use By is populated with the name from Column B of the sheet Clients

In my sheet Clients in Column A, I use a licenses dropdown populated from the Selections column in the Sheet Licenses to assign licenses to clients.

I want the dropdown to exclude any license that is already assigned to a client but don't know how.

Using the example data below, my dropdown should be populated with a single selection App_03 - satbghuyd from Licenses!A5 because the other selections in Licenses!A2:A4 are already assigned to clients in Clients!A2:A4

Example Data

Licenses

Clients

Link to my example spreadsheet