The Seven Sisters? The Peliads, Hesperides? More groups of seven here...

[link to www.mysticalnumbers.com]

The "Seven Sisters" was a term coined in the 1950s by businessman Enrico Mattei, then-head of the Italian state oil company Eni, to describe the seven oil companies which formed the "Consortium for Iran" and dominated the global petroleum industry from the mid-1940s to the 1970s. The group comprised Standard Oil of New Jersey and Standard Oil Company of New York (now ExxonMobil); Standard Oil of California (now Chevron), Gulf Oil (acquired by Chevron in 1985) and Texaco; Royal Dutch Shell; and Anglo-Persian Oil Company (now BP).

In 1973 the members of the Seven Sisters controlled 85% of the world's petroleum reserves but in recent decades the dominance of them and their successor companies has been reduced by the increasing influence of the OPEC cartel and state-owned oil companies in emerging-market economies