I don't think you need a filter. The games that are recruiting are near the top. It's like most free rpg spaces. There's way more ppl wanting to play, than ppl wanting to dm/gm/keeper...
Games don’t stay open for long generally, they get advertised in the tavern , fill up then close. Sometimes a game might have dropouts and recruit and they’ll appear in the tavern again. Just keep an eye out there.
If you are talking about the Games page, you can enter the system name in the search bar. This page isn't the best way to find games, but it might still be useful. :D
If you are talking about Games Tavern subforum, then no.