Just a crazy idea...but serious.
YOU should start holding these meetings you are talking about. Invite all the players and do it all very publiclyby also inviting newspaper,TV,ETC. When the meeting/s are done, very publicly, get the word out as to who was there, and more importantly, who was not there.

Shine the harsh light of publicity and public criticism on these folks and you'll find it goes a lot further than hoping some of them will do the right thing. You need to publicly shame them into it!

Stick with it. It'll be hard because few will come at first. But when they see their name in the media listed as among those who apparently don't care, they'll start showing up.