Hello! New person here,
For the Fortress Survival group, maybe give Disqus a shot? It's completely free and from the FAQ it says it can support however many people for free http://puu.sh/nzTXE/ce78cb695e.png
While I'm not sure if the voice server is free or not to set up, there's no lag and you can have multiple channels per group to keep it filtered nicely (eg: gameinvites/chat) as well as PMs
For people who don't want to download another program, this can be run in a browser.
Just a thought since I was told the Skype group doesn't work so well
Edit: Quick access to FAQ for those interested! https://help.disqus....ns-about-disqus
Edited by Ariel, 08 March 2016 - 09:47 PM.