Intermediary:

 A financial institution such as a bank or savings and loan, that acts as a conduit between suppliers of funds (depositors) and users of funds (borrowers). An intermediary is also a person acting as a broker between any seller and buyer; a go-between, agent, or mediator.  The intermediary's job is to negotiate prices, terms and conditions, delivery, etc., presenting the completed package to each party.

The Scam: The UNDERGROUND NETWORK consists only of intermediaries.  An alleged deal may begin in North Africa somewhere with a guy who thinks he has a contact for a gold sale.  He calls Joe who call Mary who calls Françoise and so on until the deal ends up in Melbourne with a bloke who thinks he has a gold buyer.  If there are more than three or four intermediaries involved, the line of intermediaries is called a "daisy chain."  In fact, none of these "deals" ever go anywhere and are really just an exercise in futility.  It is virtually impossible to figure out the source of the deals or their real purpose.  As best as I can determine, somewhere at the top of the chain is a person who feels that there just may be a sucker somewhere down the line who will actually fall for the proposed deal.  Besides gold in all its forms, phony deals are offered for wheat, sugar, frozen chicken, cigarettes, oil, precious gems, precious metals, fertilizer, scrap ships, precious woods, infrastructure loans, self-liquidating loans, financial instruments, and trade programs also known as HIGH-YIELD INVESTMENT PROGRAMS (hyip).