Trade Guild

association of people in a single profession/craft

typically focused on protecting the livelihood of its members by keeping out fresh competition (Barriers To Entry)

http://en.wikipedia.org/wiki/Guild

Thomas Malone said that Free Agent-s need a Trade Guild, back in 1997. In other words, an organization that provides a home for individuals of the sort that our large companies do today, but in a way that is orthogonal to the temporary task networks that actually do the work. One of the words we've ended up using for these organizations is the word guild. By analogy to the guilds in the Middle Ages. These guilds could arise from a variety of sources today, from professional societies, from college alumni associations, from unions, from families, from neighborhoods, from churches.

cf Labor Union, Occupational Licensing