Pop-up with Available id only

[patrickd123]

Hi,

Given this table(Meetings)

EmployeeID
Date
Hour (Discreet values like: 0900,0945,1030,..... contained in a linked table)

In my Mettings entry form, I would like to program a popup in the Hour field to show the available hours(not already taken) for the current employee.

Can you give me some hints?

Thanks