Skype and monitored conference calls

I live in Tokyo and have a 1-800 number for North America which gets forwarded to my N.A. Skype number and I receive the call in Tokyo on my computer.

That's great!

But here is what I want to do. I have a web site that provides services around the world via freelancers from around the world who have registered with me. I do not allow direct contact between providers and clients (they communicate through my website), but I get many requests from clients who want to talk to their freelancer on the phone.

I would like to be able to connect the clients around the world to the freelancer through me. That is, all calls would be monitored by me as the third party on the line. However, I am not sure if this can be done or how it would work.

Of course both parties would be informed that the call is being monitored and/or recorded. I would probably have to have a Skype number in the country of each party ($70 per year per country) but from there how do I connect the client from that country who calls that number to another number in another country or even in the same country and at the same time allow me to monitor the calls?

I don't know where to go from here. Any ideas?