With all due respect, you sound like someone from a privileged first-world country which has more-or-less a "free" telephone call program. Such is hardly the case for my intended use.

In my case, one of the callers would be based in a country listed by the United Nations as a "Least Developed Country." Not only would the calls be expensive, but there would be insufficient ability to earn the amount required to cover those costs within that country. Furthermore, the government of that country severely limits the infusion of funds from other nations to private individuals within the country, and it is extremely difficult, if not impossible, to get any funding through, especially to a local (foreigners may be able to use their own foreign bank accounts to withdraw funds at an ATM).

I am not specifying the name of the country for multiple reasons, not merely for my own privacy here. This is a country in which non-profit organizations are not recognized, foreign (and even local) foundations are near impossible to establish, and the government opposes any form of grass-roots community action that is not led out by the government itself. Books of many types cannot be sold within the country, or imported, including Bibles--such is the nature of its government. The full extent to which the government monitors internet communications within the country or across its borders is unknown. A secure encryption of all communications would be advisable.

The circumstances are what they are. I would certainly not be considering going this route without reason. Honestly, this task is daunting to me and having looked into Djabberd and Jitsi and Asterisk, I have yet to find any plausible path to success.

Djabberd did not install correctly on my machine, and seems to be requiring one missing library which is no longer available. Asterisk seems more for first-world countries with good telephony systems. And I just haven't figured out yet what Jitsi is or can do. The task may be beyond my skills, which I knew was a possibility when I asked the question--but one can never get an answer to that which one has not first asked.

Without this form of communication, the international public-interest project it stood to benefit will be greatly hampered. I'm considering hiring some help, having found freelancer.com, but don't know yet how that works.