For an important project I am seeking former or retired investment bankers who specialized in telecommunications. What social networking websites are popular with this group of professionals?

For this project it would be necessary that the telecom investment bankers were working in this field from about 1997 until about 2008, (or after 2008). A specialty in analysis of cellular systems like Verizon, T-Mobile, and other cell phone system providers is essential. They would be paid the standard hourly rate for this project which should take a few months or more.