Would it be possible to implement a tag item that displays FCOPX and if no FCOPX is detected it will hide the FCOPX field and display the ADES and vice versa. So traffic that is exiting the FIR would have the FCOPX displayed and traffic landing in the FIR will have the ADES displayed.
We are trying to simulate the system used in the UAE and this is how the tags are set up IRL (picture examples below taken from this video)