This is actually how a Southern polyamory group keeps out hamplanets who say "I'm polyamorous" because they're desparate.  Have the group meet at someone's apartment atop a stairwell, and the "I'm polyamorous" Tumblrinas won't show up because they don't want to climb stairs. I have yet to see this practice implemented with other types of groups that need a ham filter like lesbian groups or BDSM, but it's an intriguing idea that's proven to work.