On the series site on AO3 there is a status field for the completion of the series.
Under "Stats:" itīs a sub-item called "Complete:" with either "No" or "Yes".
Would it be possible to use this for the status column of the series anthology?
example:
completed (YES) -
https://archiveofourown.org/series/254860
in-progress (NO) -
https://archiveofourown.org/series/482902