Pop-up winldow for many to many relationship

Pop-up winldow for many to many relationship

  
Hi, I have the following entities:

Person
Building
Key

The idea is to track which of our staff have keys for our different buildings. So, each Key entity has a BuildingId attribute, as the key relates to a specific building.

I have also created a PersonKey entity - this contains a PersonId and a KeyId - this is the join table. Using IntelliWarp, I've dragged the PersonKey entity onto the ShowPerson screen - this has added a pop-up editor which allows me to add new keys held by this Person.

All that is working fine. The issue is that the pop-up window for linking new keys to the person only shows one field in a drop-down - the description of the key. However, I would like the pop-up to either:
  • show a composite field instead of just the key description (e.g. key description and building name - "Front door key - North St")
  • OR have a building drop-down that would allow me to first select a building, and then only show keys from that building that I could then select from
I'm afraid I'm new to Outsystems, and I can't find an example that customises a pop-up window to allow sub-selecting or composite fields in this way. Any help gratefully received...