This is still not possible and is much more complex than simply adding a new filter. It is a limitation in the database schema and would require a major update with a forced database update for all players. The last time we did a forced database schema update it caused a lot of unexpected issues so this is unlikely to happen in HM2. Hopefully it will be possible in HM3.
Appreciate the update, at least we can make due with what we have available still even if its a little sub optimal.