Extract unique values out of list based on an extra criteria

Hello,

I have been searching and trying many examples to get an list of unique values out of a dataset. Attached you'll find the worksheet with the data and what the expected output should be.

I managed to extract unique values without the additional criteria using the following array formula:

={INDEX(tbl_AR[ID];MATCH(0;COUNTIF($A$5:A5;tbl_AR[ID]);0))}

The results are all the unique values of the dataset, in this case tbl_AR (around 8800 rows).

The problem:
I don't manage to find the correct formula whereby only the unique values are extracted when administration = [parameter]. In this example 6003.
I tried to work with function rows but then i get the error that formula is too long


Any tips and / or guidance would be highly appreciated.

Thx in advance,

Sven